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ATOLL RESEARCH BULLETIN

192. THE NATURAL HISTORY OF JOHNSTON ATOU, L PAUFIC OCEAN

by A. Binion

Jr.,

4 PhBi C Shehon

Tmued by

THE SNITHSONIAN INSTITUTION

W d i m g t o n , D.C.,

U.S.A.
(2)

In Atoll Research Bulletin //I86 the names of the authors, Roger B. Clapp and William 0. Wirtz, 11, were accidently omitted from the covet^.

On the title page of #186 the publication information at the bottom should have read as it appears below. The part of this page below the dotted line may be cut out and pasted over the bottom of the

title page of ij186.

Issued by

The Smithsonian Institution with the assistance of The Fish and Wildlife Service U.S. Department of the Interior

Washington,

D.

C.,

U.S.A.

February 15, 1975

In

ARB

11184 a line was omitted in final typing. On page 5, in paragraph

4,

line 4, after the word nesting there should be inserted

11 does occur to some extent. It was not determined if increased nest- ing".

We regret the occurrence of these errors.--Eds.

(3)

ATOLL RESEARCH BULLETIN NO. 192

THE NATURAL HISTORY OF JOHNSTON ATOLL, CENTRAL PACIFIC OCEAN

by

A. Binion Amersoi~,

Jr.,

and Philip C. Shelton

I s s u e d by

THE SMITHSONIAN INSTITUTION w i t h t h e a s s i s t a n c e of The F i s h and W i l d l i f e S e r v i c e U. S. Department of t h e I n t e r i o r

Washington, D. C . , U.S.A.

December, 1976

(4)

ACKNOWLEDGMENT

The A t o l l Research B u l l e t i n i s i s s u e d by t h e Smithsonian I n s t i - t u t i o n a s a p a r t of i t s T r o p i c a l Biology Program. I t i s co-

sponsored by t h e Museum of N a t u r a l H i s t o r y and t h e Smithsonian P r e s s . The P r e s s s u p p o r t s and h a n d l e s p r o d u c t i o n and d i s t r i b u t i o n . The e d i t i n g i s done by t h e T r o p i c a l Biology s t a f f , Botany Department, Museum o f N a t u r a l H i s t o r y and by

D.

R, S t o d d a r t .

The B u l l e t i n was founded and t h e f i r s t 117 numbers i s s u e d by t h e P a c i f i c Science Board, N a t i o n a l Academy of S c i e n c e s , w i t h f i n a n c i a l s u p p o r t from t h e O f f i c e of Naval Research. I t s pages were l a r g e l y devoted t o r e p o r t s r e s u l t i n g from t h e P a c i f i c Science Board's Coral A t o l l Program.

The s o l e r e s p o n s i b i l i t y f o r a l l s t a t e m e n t s made by a u t h o r s of p a p e r s i n t h e A t o l l Research B u l l e t i n r e s t s w i t h them, and s t a t e m e n t s made i n t h e B u l l e t i n do n o t n e c e s s a r i l y r e p r e s e n t t h e views of t h e

Smithsonian n o r t h o s e of t h e e d i t o r s of t h e B u l l e t i n .

Editors

F. R. Fosberg M.-H.. Sachet

Smithsonian I n s t i t u t i o n Washington, D . C. 20560 D. R. S t o d d a r t

Department of Geography U n i v e r s i t y of Cambridge Downing P l a c e

Cambridge, England

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TABLE OF CONTENTS

L i s t of F i g u r e s

...

v

L i s t of Tables

...

x i v

..

L i s t of Appendix Tables

...

-xvix

...

I n t r o d u c t i o n

... ...

1

P h y s i c a l Environment

.. . . . ~ . . o ~ ~ . . .

3

I s l a n d s

... ...

3

Geology

...

7

...

Geomorpholo gy 1 2 Climate

...**...*...

* . 15

...

Temperature 1 5 Winds

...

15

P r e c i p i t a t i o n

...

1 8

...

R e l a t i v e Humidity 22 Sky Cover

...

22

Oceanography

. . . 9 . * a e . . . o . . . ..

24

Major Water Masses and C u r r e n t s

...

24

Local Waters and C u r r e n t s

... 26

Tides . . . a . . . e . o . . a . . . . a

..

30

Seismic o r Tsunami Waves

...

30

H i s t o r y . . . a e . . . 9 . 3 * . . . o 9 e . . . e . . + a .

..

30

Discovery and E a r l y E x p l o r a t i o n

...

32

Guano P e r i o d

...

34

M i l i t a r y Occupation

... ...

43

B i o t a

...

47

P l a n t s

...

4 7 Algae

. . . o . . . 9 . . . * . . . a . . .

47

Vascular P l a n t s

...*...

5 1 O r i g i n a l F l o r a

. ...

5 1 Recent V e g e t a t i o n

...

61

I s l a n d account^...^... 62

Akau I s l a n d

...

62

Hikina I s l a n d

...

63

J o h n s t o n I s l a n d

. ...

63

Sand I s l a n d

...

65

O r i g i n a l

...

65

Man-made

...

65

I n v e r t e b r a t e s

...o.aa...a...

65

C n i d a r i a ( C o e l e n t e r a t a )

...a*....s

67 Molluscs.

...*...

7 0 Annelida

...

70

Arthropoda

...

70

Marine

...

70

T e r r e s t r i a l

...

77

Medically Important S p e c i e s

...

79

I x o d i d e s

...

79

Trombiculidae

...

84

Rhinonyssidae

...

86

Mallophaga

...

86

Hippoboscidae

...

86
(6)

Echinodermata

...

86

V e r t e b r a t e s

...

86

F i s h e s

...

89

...

P e l a g i c F i s h e s 89

...

I n s h o r e F i s h e s 90

...

D i s t r i b u t i o n and Abundance Within t h e A t o l l 90

...

E f f e c t s of Dredging 92

...

C i g u a t e r i c F i s h e s 103

...

S p e c i e s Accounts 110

...

Moray E e l 110

...

S u r g e o n f i s h e s 111 R e p t i l e s

...

1 1 2

...

S p e c i e s Accounts 112

...

Black Sea T u r t l e 112 House Gecko

...

113

...

Fox Gecko 113

...

Mourning Gecko 113

...

Snake-eyed Skink 113 B i r d s

...

1 1 4

...

I n t r o d u c t i o n 116

...

S e a b i r d s 118

...

Breeders 118

...

Former Breeders 118

...

V i s i t o r s 118

...

Waterfowl. Marsh. and Land B i r d s 119

...

Regular Migrants 119

...

~ r r e g u l a r V i s i t o r s 119

...

S t r a g g l e r s 1 1 9 A c c i d e n t a l s

...

119

...

I n t r o d u c t i o n s 119

...

Annual Cycles 119

...

Breeding Cycles 120

...

Winter and S p r i n g 120

...

S p r i n g and Summer 120 Summer

...

122

Summer and F a l l

...

122

Extended

...

122

P o p u l a t i o n Cycles

...

122

Breeding S e a b i r d s

...

1 2 2 Former Breeding S e a b i r d s

...

125

Regular Migrants

...

125

I r r e g u l a r V i s i t o r s . S t r a g g l e r s . and A c c i d e n t a l B i r d s

...

125

I n t r o d u c e d B i r d s

...

126

At-Sea B i r d s

...

126

E f f e c t s of Weather P a t t e r n s

...

134

...

E c o l o g i c a l D i s t r i b u t i o n W i t h i n t h e A t o l l 135 S e a b i r d s

...

135

Breeding

...

135

...

V i s i t o r s 135

(7)

...

Waterfowl. Marsh. and Land Birds 135

...

Regular Migrants 135

Irregular Visitors. Stragglers. and 135

Accidentals

...

135

...

Introductions 135

...

Island Accounts 136

...

Akau Island 136

...

Hikina Island 136

...

Johnston Island 136

...

Sand Island 137

...

Mortality 139

...

Banding and Interisland Movement 141

...

Banding 141

...

Interisland Movement 141

...

Avifaunal Affinities 145

...

Techniques 148 Specimens

...

149

...

Species Accounts 151 Black-footed Albatross

...

151

...

Laysan Albatross 153 Phoenix Petrel

...

155

Bulwer's Petrel

...

155

Wedge-tailed Shearwater

...

165

Christmas Shearwater

...

178

Newell's Shearwater

...

187

Sooty Storm Petrel

...

188

Red-billed Tropicbird

...

188

Red-tailed Tropicbird

...

192

White-tailed Tropicbird

...

205

Blue-faced Booby

...

206

Brown Booby

...

213

Red-footed Booby

...

229

Great Frigatebird

...

244

Lesser Frigatebird

...

260

Cattle Egret

...

260

...

Pintail 262 American Wigeon

...

265

Northern Shoveler

...

266

Domestic Chicken

...

266

Peregrine Falcon

...

266

American Golden Plover

...

267

Black-bellied Plover

...

273

Semipalmated Plover

...

273

Bristle-thighed Curlew

...

274

Lesser Yellowlegs

...

274

Spotted Sandpiper

...

277

Willet

...

278

Wandering Tattler

...

279

Ruddy Turnstone

...

281

Dowitcher species

...

286

Sanderling

... ...

287
(8)

...

Western S a n d p i p e r 289

P e c t o r a l S a n d p i p e r

...

289

S h a r p - t a i l e d S a n d p i p e r

...

291

B u f f - b r e a s t e d Sandpiper

...

292

Ruff

...

292

...

~ i l s o n ' s P h a l a r o p e 293

...

Glaucous-winged G u l l 293 H e r r i n g G u l l

...

294

Laughing G u l l

...

294

F r a n k l i n ' s G u l l

...

295

G u l l s p e c i e s

...

296

Gray-backed T e r n

...

297

Sooty T e r n

...

305

E l e g a n t Tern

...

322

Blue-gray Noddy

...

322

Brown Noddy

...

323

Black Noddy

...

337

White T e r n

...

345

Rock Dove

...

350

S h o r t - e a r e d O w l

...

351

...

S k y l a r k 353

...

J a p a n e s e White-eye 354 S o c i e t y F i n c h

...

355

...

Mammals 355 S p e c i e s Accounts

...

355

House Mouse

...

356

Roof R a t

...

358

Domestic Dog

...

359

...

Domestic C a t 360

...

Hawaiian Monk S e a l 361

...

European R a b b i t 361

...

E c o l o g i c a l S i g n i f i c a n c e 361

...

E c o l o g i c a l Values of J o h n s t o n A t o l l 361

...

J o h n s t o n A t o l l : Some E c o l o g i c a l C o n s i d e r a t i o n s 362 The P l a c e of J o h n s t o n A t o l l i n t h e N a t u r a l

...

B i o s p h e r e 362 The I m p o r t a n c e of J o h n s t o n A t o l l a s a S c i e n t i f i c

...

L a b o r a t o r y 363

...

F u t u r e P o t e n t i a l 364

...

E c o l o g i c a l S i g n i f i c a n c e of J o h n s t o n A t o l l 365

...

J o h n s t o n A t o l l : E c o l o g i c a l S i g n i f i c a n c e 367

...

summary 369

...

Acknowledgments 369

...

L i t e r a t u r e C i t e d 372

...

Addendum 383 Appendix Tables

...

385
(9)

LIST OF FIGURES F i g u r e

1. Efap of t h e c e n t r a l P a c i f i c Ocean.

2. Map o f J o h n s t o n A t o l l ; a d a p t e d f r o m Wennekens (1969) and Ashmore (1973).

3. L o o k i n g n o r t h e a s t o v e r J o h n s t o n and Sand I s l a n d s from 3 , 0 0 0 f e e t , 1 2 November 1935 (U.S. N a t . A r c h i v e s , R.G. 8 0

p h o t o g r a p h ) .

4 . The n o r t h e a s t end o f J o h n s t o n I s l a n d a s i t a p p e a r e d from t h e s o u t h i n 1 9 2 3 (B.P. B i s h o p Museum p h o t o g r a p h by R.S.

p a l m e r )

.

5 . J o h n s t o n I s l a n d , s e e n f r o m t h e n o r t h a t 3,500 f e e t ,

1 0 O c t o b e r 1 9 3 9 (U.S. N a t . A r c h i v e s , R.6. 8 0 p h o t o g r a p h ) . 6 . Looking n o r t h o v e r J o h n s t o n I s l a n d , 9 A p r i l 1942 (U.S.

Nat. A r c h i v e s , R.G. 8 0 p h o t o g r a p h ) .

7 . P r o f i l e map of J o h n s t o n I s l a n d , J o h n s t o n A t o l l , 1 9 2 3 , 1 9 4 2 , and 1964; a d a p t e d from Ashmore (1973) and USNOO C h a r t No. 5356, 20 May 1963 and 23 December 1967.

8 . Sand I s l a n d from t h e n o r t h , p r o b a b l y i n 1 9 3 9 (U.S. Nat.

A r c h i v e s , R.G. 8 0 p h o t o g r a p h ) .

9 . Sand I s l a n d from t h e s o u t h e a s t , 1 8 March 1 9 4 0 ; b u i l d i n g s l a t e r c o v e r e d t h e e n t i r e i s l a n d , i n c l u d i n g t h e n o r t h e a s t p e n i n s u l a (U.S. N a t . A r c h i v e s , R.G. 8 0 p h o t o g r a p h ) . 1 0 . Sand I s l a n d a s i t a p p e a r e d f r o m t h e s o u t h e a s t a b o u t

1 9 6 2 , w i t h t h e U.S. C o a s t Guard LORAN S t a t i o n c o m p l e t e d ( o f f i c i a l U.S. C o a s t Guard p h o t o g r a p h ) .

11. Sand I s l a n d a s i t a p p e a r e d from t h e w e s t , circa 1 9 6 5 , a f t e r 1964 c o n s t r u c t i o n had added a few a c r e s t o t h e s o u t h s i d e of t h e man-made p o r t i o n of t h e i s l a n d ( o f f i c i a l U.S.

C o a s t Guard p h o t o g r a p h ) .

1 2 . J o h n s t o n A t o l l r e e f p r o f i l e s ; a d a p t e d from Emery (1956) and Wennekens ( 1 9 6 9 ) . A : o u t e r r e e f ; B : i s o l a t e d p a t c h r e e f s .

1 3 . Sequence of s e a l e v e l c h a n g e s , J o h n s t o n A t o l l (Ashmore, 1 9 7 3 ) .

f a c i n g 1

1 4 . Mean m o n t h l y a i r and s e a t e m p e r a t u r e s , J o h n s t o n A t o l l , 1931-1972; a i r : ( s o l i d l i n e ) , d a i l y maximum and minimum

( d a s h e s ) , e x t r e m e s ( d o t s ) ; s e a : means ( b a r r e d ) . Adapted from S e c k e l (1962) and U.S. D e p a r t m e n t of Commerce ( 1 9 7 2 ) .

(10)

F i g u r e

1 5 . P e r c e n t f r e q u e n c y of wind from E a n d ENE (open b a r ) a n d

ESE and NE ( s t i p p l e d b a r ) , J o h n s t o n A t o l l . 17 1 6 . Mean m o n t h l y wind s p e e d , J o h n s t o n A t o l l , 1931-1972;

means ( s o l i d l i n e ) , u p p e r e x t r e m e s ( d o t s ) . Adapted from

U.S. Department of Commerce ( 1 9 7 2 ) . 17

1 7 . J o h n s t o n A t o l l mean U components; a d a p t e d from J o i n t

Task F o r c e Seven ( 1 9 5 9 ) . 1 9

1 8 . J o h n s t o n A t o l l mean V components; a d a p t e d from J o i n t

T a s k F o r c e Seven ( 1 9 5 9 ) . 1 9

1 9 . Mean m o n t h l y p r e c i p i t a t i o n , J o h n s t o n A t o l l , 1931-1972;

means ( s o l i d l i n e ) , e x t r e m e s ( d o t s ) , Adapted from U.S.

D e p a r t m e n t of Commerce ( 1 9 7 2 ) . 2 0

20. Mean m o n t h l y r e l a t i v e h u m i d i t y , J o h n s t o n A t o l l , 1931- 1 9 7 2 ; 0100 h o u r s ( d o t s ) , 0700 h o u r s ( d a s h e s ) , 1300 h o u r s ( s o l i d l i n e ) , 1900 h o u r s ( b a r r e d ) . Adapted from

U.S. Department o f Commerce ( 1 9 7 2 ) . 2 1

21. Mean m o n t h l y s k y c o v e r , s u n r i s e t o s u n s e t , J o h n s t o n A t o l l , 1931-1972. Sky c o v e r i s e x p r e s s e d i n a r a n g e of 0 t o 3 a s b e i n g c l e a r , 4 t o 7 p a r t l y c l o u d y , and 8 t o 1 0 c l o u d y . Adapted from U.S. D e p a r t m e n t of

Commerce ( 1 9 7 2 ) .

22. Mean m o n t h l y number o f d a y s of c l e a r s k i e s ( s o l i d l i n e ) , p a r t l y c l o u d y s k i e s ( d o t s ) , c l o u d y s k i e s ( b a r r e d ) , and p r e c i p i t a t i o n of 0 . 0 1 i n c h o r more ( d a s h e s ) , J o h n s t o n A t o l l , 1931-1972. Adapted from U.S. Department o f

Commerce ( 1 9 7 2 ) . 2 3

23. P a c i f i c Ocean c u r r e n t s (King, 1 9 6 7 ) . 25

24. S e a s o n a l and t i d a l f l o w r e g i m e s , J o h n s t o n Atoll.

(Wennekens, 1 9 6 9 ) .

25. J o h n s t o n A t o l l i n f e r r e d l a g o o n c i r c u l a t i o n , J a n u a r y -

F e b r u a r y 1965 (Kopenski and Wennekens, 1.966). 28

26. J o h n s t o n A t o l l i n f e r r e d l a g o o n c i r c u l a t i o n and t u r b i d o u t f l o w ( w e s t e r l y f l o w ) , J u l y - A u g u s t 1965 (Kopenski

and Wennekens

,

1 9 6 6 )

.

29

27. J o h n s t o n A t o l l i n f e r r e d c i r c u l a t i o n and t u r b i d o u t f l o w ( e a s t e r l y f l o w ) , July-August 1 9 6 5 (Kopenski and Wenne-

k e n s , 1 9 6 6 ) . 2 9

28. T i d a l wave r e c o r d s , J o h n s t o n A t o l l (Wennekens, 1 9 6 9 ) . 3 1

(11)

F i g u r e

29. A l g a e c o l l e c t i o n s t a t i o n s , J o h n s t o n A t o l l , 1965-1966 (Buggeln and T s u d a , 1 9 6 9 ) .

30. D i s t r i b u t i o n o f t h e f i v e m o s t i m o o r t a n t p l a n t s p e c i e s on t h e o r i g i n a l p o r t i o n o f Sand I s l a n d , J o h n s t o n A t o l l , J u l y - A u g u s t 1 9 6 3 .

31. D i s t r i b u t i o n of dominant p l a n t s p e c i e s on t h e o r i g i n a l p o r t i o n o f Sand I s l a n d , J o h n s t o n A t o l l , May 1967.

32. J o h n s t o n A t o l l showing i n v e r t e b r a t e and f i s h c o l l e c t i o n s t a t i o n s , d r e d g e d a r e a s , and t h e e x t e n t of s i l t l a d e n w a t e r (Brock,

et a t . ,

1 9 6 6 ) .

3 3 . D i s t r i b u t i o n o f p o s i t i v e s a m p l e s o f

Ornithodoros capensis

f o r 1 9 6 5 , Sand I s l a n d , J o h n s t o n A t o l l . . I n s e r t s show b i - m o n t h l y i n f e s t a t i o n r a t e s f o r t h e

t h r e e m a j o r a r e a s .

3 4 . Bi-monthly t i c k i n f e s t a t i o n r a t e s ( s t i p p l e s ) compared w i t h b r e e d i n g b i r d p o p u l a t i o n f l u c t u a t i o n s ( b a r s ) , Sand I s l a n d , J o h n s t o n A t o l l , 1 9 6 5 .

35. A r e a s u s e d by S o o t y T e r n s and Wedge-tailed S h e a r w a t e r s on Sand I s l a n d , J o h n s t o n A t o l l , 1 9 6 5 .

36. F i s h c o l l e c t i o n s t a t i o n s , J o h n s t o n A t o l l , 1963-1964 (Brock,

et a t . ,

1 9 6 5 ) .

37. B r e e d i n g c y c l e s of s e a b i r d s a t J o h n s t o n A t o l l ; s t i p p l e d a r e a r e p r e s e n t s e g g s , b a r r e d a r e a y o u n g , and h l a c k d o t s n o n - b r e e d i n g b i r d s .

38. Monthly c u m u l a t i v e b i r d p o p u l a t i o n s , J o h n s t o n A t o l l , 1963-1969.

39. Monthly mean s h o r e b i r d p o p u l a t i o n s f o r J o h n s t o n A t o l l , 1963-1969; Golden P l o v e r ( s o l i d l i n e ) , Ruddy T u r n s t o n e

( d o t s )

,

Wandering T a t t l e r ( d a s h e s )

.

40. D i u r n a l b i r d p o p u l a t i o n s a t s e a 1 7 5 m i l e s s o u t h w e s t of J o h n s t o n A t o l l , 1963-1967.

41. Monthly d i u r n a l p o p u l a t i o n f l u c t u a t i o n s w i t h i n t h e a t - s e a g r i d by s p e c i e s g r o u p , 1963-1967.

4 2 . T o t a l n o c t u r n a l b i r d s i g h t i n g s a t s e a 175 m i l e s s o u t h w e s t of J o h n s t o n A t o l l , 1963-1967.

43. N e s t i n g a r e a s of ground

nest in^

b i r d s ( e x c e p t S o o t y T e r n s ) on t h e - o r i g i n a l p o r t i o n of sand I s l a n d , ~ o h n s t o n

Gall,

1 9 6 3 .

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F i g u r e

44. N e s t i n g a r e a s o f b i r d s which n o r m a l l y n e s t i n l o w v e g e t a t i o n on t h e o r i g i n a l p o r t i o n of Sand I s l a n d , J o h n s t o n A t o l l , 1 9 6 3 .

45. B u l w e r ' s P e t r e l c h i c k , a b o u t 2 months o l d , i n f r o n t of r o c k c r e v i c e n e s t s i t e a l o n g causeway, Sand I s l a n d , J o h n s t o n A t o l l , 25 August 1966 (POBS? p h o t o by P.C.

S h e l t o n )

.

46. C o n c r e t e s l a b s on e a s t s h o r e , a t b a s e of n o r t h e a s t p e n i n s u l a , Sand I s l a n d , J o h n s t o n A t o l l , 8 May 1 9 6 7 . C h r i s t m a s S h e a r w a t e r s n e s t e d r e g u l a r l y u n d e r t h e l a r g e s l a b s a t l e f t , and B u l w e r ' s P e t r e l s a t t e m p t e d t o n e s t a t l e a s t o n c e u n d e r t h e s l a b s i n c e n t e r of p h o t o . Brown Noddies n e s t e d i n t h e e d g e o f t h e Sesuviwn growing j u s t a b o v e t h e s t o r m b e a c h (POBSP p h o t o by P.C. S h e l t o n ) .

47. D i s t r i b u t i o n of B u l w e r ' s P e t r e l n e s t s i t e s , Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969.

48. Means and e x t r e m e s of s e m i m o n t h l y e s t i m a t e s of B u l w e r ' s P e t r e l numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969.

4 9 . D i u r n a l o c c u r r e n c e of B u l w e r ' s P e t r e l s a t s e a 1 7 5 m i l e s s o u t h w e s t o f J o h n s t o n A t o l l . , 1963-1967.

5 0 . D i s t r i b u t i o n of W e d g e - t a i l e d S h e a r w a t e r n e s t s i t e s on Sand I s l a n d , J o h n s t o n A t o l l , 1963-3969. Numhers i n d i - c a t e c h i c k s banded i n 1 9 6 8 .

5 1 . Wedge-tailed S h e a r w a t e r c h i c k i n f r o n t of b u r r o w u n d e r L e p t u r u s r e p e z s c l u m p s , Sand I s l a n d , J o h n s t o n A t o l l ,

2 September 1966 (POBSP p h o t o by P.C. S h e l t o n ) .

5 2 . Wedge-tailed S h e a r w a t e r s among Tr'ribuZus, B o e r h a v i a , and L e p t u r u s on s o u t h w e s t Sand I s l a n d , J o h n s t o n A t o l l , mid- morning J u l y 1 9 6 3 (POBSP p h o t o by A . B . Amerson, J r . ) . 5 3 . Means and e x t r e m e s of semimonthly e s t i m a t e s o f Idedge-

t a i l e d S h e a r w a t e r numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

5 4 . D i u r n a l o c c u r r e n c e of W e d g e - t a i l e d S h e a r w a t e r s ( l i s h t p h a s e ) a t s e a 175 m i l e s s o u t h w e s t of J o h n s t o n A t o l l , 1963-1967.

5 5 . C h r i s t m a s S h e a r w a t e r c h i c k , 2 and 1 / 2 months o l d , i n s h a l l o w t r e n c h b u r r o w u n d e r L e p t u r u s r e p e n s clump on e a s t s h o r e of Sand I s l a n d , J o h n s t o n A t o l l , 29 August 1966 (POBSP p h o t o by P.C. S h e l t o n ) .

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F i g u r e

56. C h r i s t m a s S h e a r w a t e r c h i c k , 2 months o l d , and a d u l t s i n b u n k e r on e a s t s h o r e , Sand I s l a n d , J o h n s t o n A t o l l , 1 September 1966 (POBSP p h o t o by P.C. S h e l t o n ) .

5 7 . D i s t r i b u t i o n of C h r i s t m a s S h e a r w a t e r n e s t s i t e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

58. Means and e x t r e m e s of semimonthly e s t i m a t e s o f C h r i s t m a s S h e a r w a t e r numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1964- 1 9 6 9 .

5 9 . D i s t r i b u t i o n of R e d - t a i l e d T r o p i c b i r d n e s t s on Sand I s l a n d , J o h n s t o n A t o l l , 1 9 6 7 .

60. D i s t r i b u t i o n o f Red-tail.ed T r o p i c b i r d n e s t s on t h e o r i g i n a l p o r t i o n of Sand I s l a n d , J o h n s t o n A t o l l , 1 9 6 9 . 61. D i s t r i b u t i o n of R e d - t a i l e d T r o p i c b i r d n e s t s on t h e man-

made p o r t i o n o f Sand I s l a n d , J o h n s t o n A t o l l , 1969.

62. R e d - t a i l e d T r o p i c b i r d on n e s t u n d e r

T o u m e f o r t i a

b u s h n o r t h e a s t o f t r a n s m i t t e r b u i l d i n g , Sand I s l a n d ,

J o h n s t o n A t o l l , 25 F e b r u a r y 1967 (POBSP p h o t o by P.C.

S h e l t o n )

.

63. Looking e a s t f r o m t o p of power b u i l d i n g , Sand I s l a n d , J o h n s t o n A t o l l , 5 September 1 9 6 9 . S e v e r a l R e d - t a i l e d T r o p i c b i r d s n e s t e d u n d e r t h e s e

Ptuchea o d o r a t a

b u s h e s

(POESP p h o t o by P.C. S h e l t o n ) .

64. Means o f semimonthly e s t i m a t e s of R e d - t a i l e d T r o p i c b i r d numbers, Sand I s l a n d , J o h n s t o n A t o l l ; 1965-1966 ( s o l i d l i n e ) compared w i t h 1967-1969 ( d o t s ) .

65. Means of semimonthly e s t i m a t e s of R e d - t a i l e d T r o p i c b i r d numbers, J o h n s t o n I s l a n d , J o h n s t o n A t o l l ; 1965-1966

( s o l i d l i n e ) compared w i t h 1967-1969 ( d o t s ) .

6 6 . D i u r n a l o c c u r r e n c e of R e d - t a i l e d T r o p i c b i r d s a t s e a 1 7 5 m i l e s s o u t h w e s t of J o h n s t o n A t o l l , 1963-1967.

67. B l u e - f a c e d Booby a d u l t and c h i c k , J o h n s t o n A t o l l , J u l y 1 9 2 3 (B.P. B i s h o p Museum p h o t o ) .

68. A r o o s t i n g c l u b of B l u e - f a c e d B o o b i e s on Sand I s l a n d , J o h n s t o n A t o l l , 2 J u n e 1 9 4 1 (U.S. N a t i o n a l A r c h i v e s , R.G.

p h o t o ) .

69. Means and e x t r e m e s of s e m i m o n t h l y e s t i m a t e s o f Blue- f a c e d Booby numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1963- 1 9 6 9 .

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F i g u r e

70. D i s t r i b u t i o n of Brown Booby n e s t s o n Sand I s l a n d , J o h n s t o n A t o l l , 1 9 6 9 .

71. Brown B o o b i e s i n e a r l y s t a g e s o f c o u r t s h i p and n e s t b u i l d i n g , e a s t h i l l of Sand I s l a n d , J o h n s t o n A t o l l , 25 F e b r u a r y 1 9 6 9 . V e g e t a t i o n i s m o s t l y

Roerhavia

w i t h s c a t t e r e d clumps of

Tribulus

(POBSP p h o t o by P.C.

S h e l t o n )

.

72. Brown Booby a d u l t s and 31-day-old c h i c k , w e s t s h o r e of n o r t h e a s t p e n i n s u l a , Sand I s l a n d , J o h n s t o n A t o l l , 9 J u l y 1966. Brown Noddies r o o s t and n e s t h e r e a l s o ; S o o t y T e r n s are i n t h e background (POBSP p h o t o by P.C.

S h e l t o n )

.

215

73. Means and e x t r e m e s o f s e m i m o n t h l y e s t i m a t e s of Brown

Booby numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969. 216 74. D i s t r i b u t i o n of Red-footed Booby n e s t s , Sand I s l a n d ,

J o h n s t o n A t o l l , 1963-1967. 231

75. Means and e x t r e m e s of s e m i m o n t h l y e s t i m a t e s of Red- f o o t e d Booby numbers, Sand ~ s l a n d , J o h n s t o n A t o l l , 1964-

1 9 6 9 . 233

76. Four Red-footed B o o b i e s n e s t i n g o n a r t i f i c i a l p l a t f o r m s (framework of a n o l d b o a t ) on t h e s o u t h e a s t b e a c h of Sand I s l a n d , J o h n s t o n A t o l l , 5 May 1 9 6 9 (POBSP p h o t o

by P.C. S h e l t o n ) . 236

77. Red-footed Booby n e s t p l a c e d o n ground on c r e s t of h i l l e a s t of t r a n s m i t t e r b u i l d i n g , Sand I s l a n d , J o h n s t o n A t o l l , 4 May 1 9 6 9 . S u b a d u l t B l u e - f a c e d Booby r o o s t i n g a t l o w e r r i g h t ; S o o t y T e r n a d u l t s and c h i c k s and Brown h'oddy a d u l t n e a r b y (POBSP p h o t o by P.C. S h e l t o n ) . 78. D i u r n a l o c c u r r e n c e of Red-footed B o o b i e s a t s e a 1 7 5

m i l e s s o u t h w e s t of J o h n s t o n A t o l l , 1963-1967.

79. G r e a t F r i g a t e b i r d n e s t i n g a r e a s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

8 0 . G r e a t F r i g a t e b i r d s n e s t i n g on g r o u n d on c r e s t of h i l l e a s t o f t r a n s m i t t e r b u i l d i n g , Sand I s l a n d , J o h n s t o n A t o l l , May o r J u n e 1 9 6 4 . S o o t y T e r n a d u l t s and c h i c k s s u r r o u n d

t h e c o l o n y (POBSP p h o t o by A . B . Amerson, J r . ) . 247 81. G r e a t F r i g a t e b i r d c o l o n y on s o u t h s h o r e , Sand T s l a n d ,

J o h n s t o n Atoll., 26 F e b r u a r y 1 9 6 9 (POBSP p h o t o by P.C.

S h e l t o n ) . 247

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F i g u r e

82. G r e a t F r i - g a t e b i r d r o o s t i n g a r e a s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

8 3 . Cleans and e x t r e m e s o f semimonthly e s t i m a t e s of G r e a t F r i g a t e b i r d numbers, Sand I s l a n d , 3 o h n s t o n A t o l l ,

1963-1969.

8 4 . D i u r n a l o c c u r r e n c e of G r e a t F r i g a t e b i r d s a t sea 175 miles s o u t h w e s t o f J o h n s t o n A t o l l , 1963-1967.

8 5 . Moving a v e r a g e s of semimonthly e s t i m a t e s o f Golden P l o v e r s , Sand and J o h n s t o n I s l a n d s combined, 1963- 1 9 6 9 .

8 6 . D i s t r i b u t i o n of Golden P l o v e r s on Sand I s l a n d , J o h n s t o n A t o l l , 26 December 1 9 6 5 .

8 7 . Moving a v e r a g e s of semimonthly e s t i m a t e s o f L7andering T a t t l e r s , Sand a n d J o h n s t o n I s l a n d s combined, 1963- 1 9 6 9 .

88. Moving a v e r a g e s of semimonthly e s t i m a t e s of Ruddy Turn- s t o n e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

89. D o w i t c h e r s p e c i e s p h o t o g r a p h e d on Sand I s l a n d , J o h n s t o n A t o l l , 8 September 1 9 6 9 (POBSP p h o t o by P.C. S h e l t o n ) . 90. Moving a v e r a g e s of semimonthly e s t i m a t e s of S a n d e r l i n g s ,

Sand and J o h n s t o n I s l a n d s , 1963-1969.

91. D i s t r i b u t i o n o f Gray-backed T e r n n e s t s i t e s , Sand I s l a n d , J o h n s t o n A t o l l , 1 9 6 6 .

92. D i s t r i b u t i o n o f Gray-backed T e r n n e s t s i t e s , Sand I s l a n d , J o h n s t o n A t o l l , 1 9 6 7 .

93. Gray-backed T e r n on n e s t ( c e n t e r f o r e g r o u n d ) among S o o t y T e r n s i n

Ipomoea

and

Lepi5u.m~

on s o u t h s h o r e of Sand I s l a n d , J o h n s t o n A t o l l , 2 1 A p r i l 1969 (POBSP p h o t o by P.C. S h e l t o n )

.

94. Gray-backed T e r n n e s t i n g a r e a on s o u t h k l e s t i s l e t , Sand I s l a n d , J o h n s t o n A t o l l , 1 6 A p r i l 1 9 6 9 . Two a d u l t s , o n e c h i c k , and f o u r e g g s a r e shown (POBSP p h o t o by P . C . S h e l t o n )

.

95. Means and e x t r e m e s of semimonthly e s t i m a t e s of Gray-backed T e r n numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969. 302

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F i g u r e

96. S o o t y T e r n s ( t i n y d o t s ) u t i l i z e a l m o s t a l l a v a i l a b l e ground n e s t s i t e s on t h e o r i g i n a l p o r t i o n o f Sand I s l a n d , J o h n s t o n A t o l l , May 1964 (mosaic by A.B.

Amerson, J r . , from POBSP p h o t o g r a p h s t a k e n a t t h e 620-foot t o w e r l e v e l by R,TJ. M e r r i l l ) .

97. S o o t y T e r n n e s t i n g a r e a s , Sand I s l a n d , J o h n s t o n A t o l l , 1967.

98. N e s t i n g S o o t y T e r n s c o v e r v i r t u a l l y t h e e n t i r e s o u t h - w e s t p o r t i o n of Sand I s l a n d , J o h n s t o n A t o l l , 1 5 A p r i l 1 9 6 9 . H o s t o f t h e Wedge-tailed S h e a r w a t e r b u r r o w s a r e u n d e r t h e L e p t u r u s i n t h i s a r e a . The s o u t h w e s t i s l e t and o l d d o c k a r e v i s i b l e a t u p p e r l e f t (POBSP p h o t o by P.C. S h e l t o n ) .

99. N e s t i n g S o o t y T e r n s n o r t h e a s t o f t h e t r a n s m i t t e r b u i l d i n g and on t h e n o r t h e a s t p e n i n s u l a , Sand I s l a n d , J o h n s t o n A t o l l , 3 0 March 1967 (POBSP p h o t o by P.C.

S h e l t o n )

.

1 0 0 . Means and e x t r e m e s o f semimonthlv e s t i m a t e s of a d u l t S o o t y T e r n numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1963- 1969.

1 0 1 . Means of semimonthly estimates of S o o t y T e r n e g g s a n d yourig, Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

1 0 2 . I n t e r i s l a n d movement of S o o t y T e r n s i n v o l v i n g t h e Hawaiian I s l a n d s , J o h n s t o n A t o l l , a n d Wake A t o l l (Gould, 1 9 7 4 b ) . 1 0 3 . D i u r n a l o c c u r r e n c e of S o o t y T e r n s a t s e a 175 m i l e s

s o u t h w e s t o f J o h n s t o n A t o l l , 1963-1967.

1 0 4 . O r a n g e - s t r e a m e r e d S o o t y T e r n s a t s e a 1 7 5 miles s o u t h w e s t of J o h n s t o n A t o l l , 1963-1967.

1 0 5 . N o c t u r n a l o c c u r r e n c e o f S o o t y T e r n s a t s e a 1 7 5 m i l e s s o u t h w e s t o f J o h n s t o n A t o l l , 1963-1967.

1 0 6 . Brown Noddy n e s t d i s t r i b u t i o n , Sand I s l a n d , J o h n s t o n A t o l l , A p r i l 1 9 6 7 .

1 0 7 , Brown N o d d i e s and S o o t y T e r n s on t h e s o u t h w e s t p o r t i o n o f Sand I s l a n d , J o h n s t o n A t o l l , J u l y 1923. J o h n s t o n I s l a n d i s v i s i b l e i n t h e background (B.P. B i s h o p Museum p h o t o by Chapman G r a n t ) .

1 0 8 . Brown N o d d i e s n e s t i n g and r o o s t i n g on t h e s o u t h w e s t i s l e t , Sand I s l a n d , J o h n s t o n A t o l l , 9 May 1967 (POBSP p h o t o by P.C. S h e l t o n ) .

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1 0 9 . Means a n d e x t r e m e s of s e m i m o n t h l y e s t i m a t e s of Brown Noddy numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1963-

1969.

1 1 0 . B l a c k Noddy n e s t i n g and r o o s t i n g a r e a s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1967.

111. B l a c k Noddy n e s t i n

Amaranthus

p l a n t s s o u t h o f t h e t r a n s m i t t e r b u i l d i n g , Sand I s l a n d , J o h n s t o n A t o l l , 7 May 1 9 6 7 . S o o t y T e r n a d u l t s and c h i c k s n e a r b y (POBSP p h o t o by P.C. S h e l t o n ) .

1 1 2 . B l a c k Noddy n e s t w i t h 12-day-old c h i c k i n

Amaranthus

p l a n t s o u t h of t h e t r a n s m i t t e r b u i l d i n g , Sand I s l a n d , J o h n s t o n A t o l l , 4 J u n e 1 9 6 9 (POBSP p h o t o by P.C.

S h e l t o n )

.

1 1 3 . Means a n d e x t r e m e s of s e m i m o n t h l y e s t i m a t e s o f B l a c k Noddy numbers, Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969.

1 1 4 . White T e r n s r o o s t i n g on u n d e r c u t b e a c h r o c k on s h o r e o f J o h n s t o n I s l a n d , .Johnston A t o l l , J u l y 1 9 2 3 (B.P. B i s h o p Museum p h o t o ) .

1 1 5 . White T e r n c h i c k h a t c h e d o n framework of o l d r a d i o t e l e s c o p e , J o h n s t o n I s l a n d , J o h n s t o n A t o l l , 1 9 J u n e 1 9 6 9 (POBSP p h o t o by P.C. S h e l t o n ) .

1 1 6 . Means and e x t r e m e s of s e m i m o n t h l y e s t i m a t e s of d i u r n a l White T e r n numbers, J o h n s t o n A t o l l , 1963-1969.

1 1 7 . D i u r n a l o c c u r r e n c e o f T%%ite T e r n s a t s e a 1 7 5 m i l e s s o u t h w e s t o f J o h n s t o n A t o l l , 1963-1967.

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LIST OF TABLES

T a b l e

-

P a g e

Ownership and c o n t r o l of J o h n s t o n A t o l l ( a d a p t e d from Bauer

,

1 9 6 5 )

.

D i s t r i b u t i o n of b e n t h i c m a r i n e a l g a e a t J o h n s t o n A t o l l . V a s c u l a r p l a n t s known from J o h n s t o n A t o l l .

C n i d a r i a ( C o e l e n t e r a t a ) from J o h n s t o n A t o l l .

D i s t r i b u t i o n and abundance of c o r a l s a t J o h n s t o n A t o l l , 1964-1965.

D i s t r i b u t i o n and abundance o f M o l l u s c a from J o h n s t o n A t o l l . A n n e l i d a from J o h n s t o n A t o l l .

M a r i n e A r t h r o p o d a from J o h n s t o n A t o l l .

I n s e c t s r e c o r d e d from J o h n s t o n A t o l l ; a d a p t e d from C h i l s o n ( 1 9 5 3 ) .

B e r l e s e s a m p l e d a t a - - 0 r n i t h o d o r o s c a p e n s i s i n f e s t a t i o n r a t e s f o r Sand I s l a n d , J o h n s t o n A t o l l , 1 9 6 5 .

Berlese s a m p l e d a t a - - b i m o n t h l y O r n i t h o d o r o s c a p e n s i s i n f e s t a t i o n r a t e s f o r Sand I s l a n d , J o h n s t o n A t o l l , 1.965.

O r n i t h o d o r o s c a p e n s i s i n f e s t a t i o n r a t e s from B e r l e s e s a m p l e s o f h o s t s ' n e s t s .

M a l l o p h a g a c o l l e c t e d a t Sand I s l a n d , .Johnston A t o l l by t h e POBSP; a d a p t e d from Amerson a n d Emerson ( 1 9 7 1 ) . E c h i n o d e r m a t a from J o h n s t o n A t o l l .

I n s h o r e f i s h e s r e c o r d e d f r o m J o h n s t o n A t o l l .

T o x i c i t y of f i s h s p e c i e s t e s t e d f o r c i g u a t e r a a t J o h n s t o n A t o l l .

B i r d s from J o h n s t o n A t o l l .

S t a t u s o f b i r d s on J o h n s t o n A t o l l .

Peak b r e e d i n g p e r i o d of J o h n s t o n A t o l l b i r d s .

N o n t h l y o c c u r r e n c e of n o n - r e s i d e n t b i r d s a t J o h n s t o n A t o l l .

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21. O c c u r r e n c e of b i r d s a t s e a i n t h e g r i d 1 7 5 miles s o u t h w e s t of J o h n s t o n A t o l l .

S t a t u s and a r e a of d e r i v a t i o n of b i r d s o b s e r v e d a t s e a n e a r J o h n s t o n A t o l l .

S o o t y T e r n m o r t a l i c y from g u y w i r e s t r i k e s , Sand I s l a n d , March-July 1 9 6 5 .

B i r d s banded a t J o h n s t o n A t o l l , 1963 t o 1 9 7 3 . Y e a r l y band r e t u r n t o t a l s f o r J o h n s t o n A t o l l .

I n t e r i s l a n d movement of banded b i r d s i n v o l v i n g J o h n s t o n Atoll.

B i r d s p e c i m e n s and summary of new r e c o r d s f r o m J o h n s t o n A t o l l .

P r o d u c t i v i t y of B u l w e r ' s P e t r e l s on Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969.

Extreme d a t e s o f s i g n i f i c a n t e v e n t s i n t h e b r e e d i n g c y c l e of B u l w e r ' s P e t r e l s on Sand I s l a n d , 1964-1969.

Banding and r e c a p t u r e s of B u l w e r ' s P e t r e l s , Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969.

P r o d u c t i v i t y o f Wedge-tailed S h e a r w a t e r s on Sand I s l a n d , J o h n s t o n A t o l l , 1963-1968.

Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e b r e e d i n g c y c l e of W e d g e - t a i l e d S h e a r w a t e r s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

Banding and r e c a p t u r e s of W e d g e - t a i l e d S h e a r w a t e r s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

P r o d u c t i v i t y of C h r i s t m a s S h e a r w a t e r s o n Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e b r e e d i n g c y c l e of C h r i s t m a s S h e a r w a t e r s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

Banding and r e c a p t u r e s of C h r i s t m a s S h e a r w a t e r s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

D i s t r i b u t i o n and n e s t i n g s u c c e s s of R e d - t a i l e d T r o p i c b i r d s by h a b i t a t t y p e , Sand and J o h n s t o n I s l a n d s , 1967-1969.

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3 8 . P r o d u c t i v i t y of R e d - t a i l e d T r o p i c b i r d s on J o h n s t o n A t o l l , 1964-1969.

I n c u b a t i o n and f l e d g i n g p e r i o d of R e d - t a i l e d T r o p i c b i r d e g g s and c h i c k s , Sand I s l a n d , J o h n s t o n A t o l l , 1967-1969.

Banding and r e c a p t u r e of R e d - t a i l e d T r o p i c b i r d s , Sand and J o h n s t o n I s l a n d s , 1963-1973.

S i g h t i n g s of W h i t e - t a i l e d T r o p i c b i r d s on J o h n s t o n A t o l l . Semimonthly p o p u l a t i o n e s t i m a t e s o f Blue-faced B o o b i e s on Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

B l u e - f a c e d Boobies banded on Sand I s l a n d , J o h n s t o n A t o l l , by t h e POBSP.

P r o d u c t i v i t y of Brown B o o b i e s , Sand I s l a n d , J o h n s t o n A t o l l , 1 9 6 3 t h r o u g h 1 9 6 9 .

S u c c e s s r a t e s of d i f f e r e n t c l u t c h s i z e s o f Brorm B o o b i e s , Sand I s l a n d , J o h n s t o n A t o l l , 1964 t h r o u g h 1969.

P e r c e n t a g e s of Brorm Eooby c h i c k s r e s u l t i n g from o n e , t w o , and t h r e e egg c l u t c h e s , Sand I s l a n d , J o h n s t o n A t o l l , 1964 t h r o u g h 1 9 6 9 .

R e n e s t i n g a t t e m p t s , i n c i d e n c e s of two c h i c k s r e a r e d i n one n e s t , and number o f c h i c k s r a i s e d by f o s t e r p a r e n t s o r by h a n d , Sand I s l a n d , J o h n s t o n A t o l l , 1964 t h r o u g h 1 9 6 9 . P e r c e n t of Brown Booby c h i c k s produced and s u c c e s s r a t e s of n e s t s by t h i . r d s of b r e e d i n g s e a s o n s , Sand I s l a n d , J o h n s t o n A t o l l , 1964 t h r o u g h 1 9 6 9 .

N e s t i n g s u c c e s s of known-age Brorvn B o o b i e s , Sand I s l a n d , J o h n s t o n A t o l l .

Extreme d a t e s o f s i g n i f i c a n t e v e n t s i n t h e Brown Booby b r e e d i n g c y c l e , Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969.

Xumber of Brown Booby n e s t s e s t a b l i s h e d by semimonthly p e r i o d s , Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969.

Banding and r e c a p t u r e s o f Brown B o o b i e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

P r o d u c t i v i t y of Red-footed B o o b i e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

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5 4 . Known a g e Red-footed Booby n e s t i n g , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e Red-footed Booby b r e e d i n g c y c l e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963- 1 9 6 9 .

Plumage r a t i o s of Red-footed B o o b i e s , Sand I s l a n d , J o h n s t o n A t o l l , 1967.

Banding and r e c a p t u r e s of Red-footed B o o b i e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1973.

P r o d u c t i v i t y of G r e a t F r i g a t e b i r d s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1967.

F a t e o f young G r e a t F r i g a t e b i r d s banded o n Sand I s l a n d , J o h n s t o n A t o l l , 1963-1967.

E x t r e m e d a t e s of s i g n i f i c a n t e v e n t s i n t h e G r e a t P r i g a t e - b i r d b r e e d i n g c y c l e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963- 1 9 6 9 .

Plumage r a t i o s of G r e a t F r i g a t e b i r d s , Sand I s l a n d , J o h n s t o n A t o l l .

O b s e r v a t i o n s of P i n t a i l s on J o h n s t o n A t o l l .

O b s e r v a t i o n s of B r i s t l e - t h i g h e d C u r l e w s on Sand I s l a n d , J o h n s t o n A t o l l , 1.963-1969.

Numbers and p e r c e n t a g e s of Ruddy T u r n s t o n e s s i g h t e d on J o h n s t o n A t o l l t h a t w e r e color-marked on S t . George I s l a n d , P r i b i l o f s , F a l l 1966.

O b s e r v a t i o n s of P e c t o r a l S a n d p i p e r s o n Sand I s l a n d , J o h n s t o n A t o l l , 1963-1968.

Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e Gray-backed T e r n b r e e d i n g c y c l e s , Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

N a r k - r e l e a s e - r e c a p t u r e c a l c c l a t i o n s o f S o o t y T e r n b r e e d i n g p o p u l a t i o n s , Sand I s l a n d , J o h n s t o n A t o l l , b a s e d on F e b r u a r y - A p r i l 1967 r e c a p t u r e s .

Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e b r e e d i n g c y c l e of S o o t y T e r n s , Sand I s l a n d , J o h n s t o n A t o l l , 1.963-1969.

O r a n g e - s t r e a m e r e d S o o t y Tern s i g h t i n g s w i t h i n a 50-mile- r a d i u s of J o h n s t o n A t o l l . and i n t h e a t - s e a g r i d :I75 miles s o u t h w e s t of J o h n s t o n A t o l l , 1964-1967.

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70. N e s t i n g m a t e r i a l used by Brown Noddies, Sand I s l a n d ,

J o h n s t o n A t o l l ; o b s e r v a t i o n s by B.A. H a r r i n g t o n , a b o u t 327 1 Play 1968.

71. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e Brown Noddy

b r e e d i n g c y c l e s , Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969. 334 72. D a i l y egg l a y i n g , h a t c h i n g , and l o s s e s f o r Brown Noddies,

Sand I s l a n d , J o h n s t o n A t o l l , July-September, 1964-1969.

73. Known-age Brown Noddy r e c a p t u r e s t a k e n from e g g s o r c h i c k s , Sand I s l a n d , J o h n s t o n A t o l l , 1967.

74. P r i m a r y m o l t s c o r e s of Brown N o d d i e s , Sand I s l a n d , J o h n s t o n A t o l l .

75. N e s t i n g s u c c e s s of B l a c k Noddies on Sand I s l a n d , J o h n s t o n A t o l l , 1963-1969.

76. C a l c u l a t i o n s of numbers of B l a c k Noddies u s i n g Sand I s l a n d , J o h n s t o n A t o l l , 1967.

77. P r i m a r y m o l t s c o r e s of Black Noddies c a u g h t r o o s t i n g on Sand I s l a n d , J o h n s t o n A t o l l , F e b r u a r y - A p r i l 1967.

78. Extreme d a t e s of s i g n i f i c a n t e v e n t s i n t h e B l a c k Noddy b r e e d i n g c y c l e s , Sand I s l a n d , J o h n s t o n A t o l l , 1964-1969.

79. O b s e r v a t i o n s of S h o r t - e a r e d Owls on J o h n s t o n A t o l l . 80. Records of J a p a n e s e White-eyes on J o h n s t o n A t o l l . 8 1 . D i s t r i b u t i o n and s t a t u s of mammals a t J o h n s t o n A t o l l . 82. Breeding c o n d i t i o n of house m i c e a u t o p s i e d , O c t o b e r 1964-

March 1965.

83. Evidence of b r e e d i n g c o n d i t i o n i n h o u s e m i c e l i v e - t r a p p e d and r e l e a s e d , October 1966 and F e b r u a r y 1967.

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LIST OF APPENDIX TABLES Appendix T a b l e

1. POBSP p e r s o n n e l p a r t i c i p a t i n g i n b i r d s t u d i e s on J o h n s t o n A t o l l , J u l y 1963-September 1969.

2 . Annotated l i s t of v a s c u l a r p l a n t ' s p e c i e s recorded from Akau I s l a n d , J o h n s t o n A t o l l .

3 . Annotated l i s t of v a s c u l a r p l a n t s p e c i e s recorded from Hikina I s l a n d , J o h n s t o n A t o l l .

4 . Annotated l i s t of v a s c u l a r p l a n t s p e c i e s recorded from Johnston I s l a n d , J o h n s t o n A t o l l .

5. Annotated l i s t of v a s c u l a r p l a n t s p e c i e s recorded from t h e man-made p o r t i o n of Sand I s l a n d , Johnston A t o l l .

6 . Annotated l i s t of v a s c u l a r p l a n t s p e c i e s r e c o r d e d from t h e o r i g i n a l p o r t i o n of Sand I s l a n d , Johnston A t o l l .

7 . Bird specimens c o l l e c t e d on J o h n s t o n A t o l l .

5. Pre-POBSP o b s e r v a t i o n s of Sooty T e r n s on Johnston A t o l l .

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.JOHNSTON ATOLL

Figure 1. Map of t h e c e n t r a l P a c i f i c Ocean.

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TIIE NATURAI, HISTORY OF JOI-INSTON ATOLL, CENTRAL PACIFIC OCEAN

11y

A. Ui11io11 Amerson, Jr., and Philip C. Sl~elton

INTRODUCTION

J o h n s t o n A t o l l c o n s i s t s of two h i g h l y modified n a t u r a l i s l a n d s and two c o m p l e t e l y man-made i s l a n d s t o t a l i n g a b o u t a s q u a r e m i l e i n s u r f a c e a r e a l y i n g on a 14 by 7 m i l e c o r a l r e e f p l a t f o r m i n t h e t r o p i c a l P a c i f i c Ocean a t 16'45'N, 16g031'W ( F i g u r e 1 ) . The n e a r e s t l a n d i s French

F r i g a t e Shoals i n t h e n o r t h w e s t e r n Hawaiian I s l a n d s , a b o u t 450 n a u t i c a l m i l e s n o r t h - n o r t h w e s t ; Honolulu, Hawaii i s 717 nm n o r t h w e s t ; t h e M a r s h a l l

I s l a n d s l i e almost 1 , 2 0 0 nm southwest, Howland I s l a n d i s 1 , 0 5 0 nm south- s o u t h w e s t , and Kingman Reef i n t h e L i n e I s l a n d s i s about 850 nm s o u t h e a s t .

Although t h e a t o l l was d i s c o v e r e d i n 1796 and claimed by t h e United S t a t e s i n 1858, i t was u n i n h a b i t e d except f o r b r i e f v i s i t s by guano m i n e r s , a d v e n t u r e r s , government s c i e n t i s t s and m i l i t a r y p e r s o n n e l u n t i l 1936,

when t h e U . S . Navy began developing f i r s t a s e a p l a n e b a s e and l a t e r an a i r s t r i p and r e f u e l i n g f a c i l i t i e s which served a s a n i m p o r t a n t l i n k from t h e Hawaiian I s l a n d s t o t h e w e s t e r n P a c i f i c d u r i n g World War 11.

A f t e r t h e war, o p e r a t i o n s diminished u n t i l t h e l a t e 1 9 5 0 ' s when t h e a t o l l was used f o r a t m o s p h e r i c n u c l e a r t e s t i n g . Although t h e l a s t t e s t s were executed i n 1962, f a c i l i t i e s have been m a i n t a i n e d " . . . f o r r e - suming n u c l e a r t e s t i n g i n t h e P a c i f i c Ocean should t h e T e s t Ban T r e a t y of 1963 b e abrogated by a f o r e i g n world power" (Bauer, 1965: 1 ) .

Most r e c e n t l y t h e a t o l l h a s become t h e s t o r a g e s i t e f o r o b s o l e t e chemical w a r f a r e a g e n t s , i n c l u d i n g n e r v e g a s f o r m e r l y s t o r e d on Okinawa, and h e r b i c i d e s used i n s o u t h e a s t A s i a .

The a t o l l was made a f e d e r a l b i r d r e f u g e by e x e c u t i v e o r d e r of

P r e s i d e n t C a l v i n Coolidge i n 1926. T h i s o r d e r remains i n e f f e c t , a l t h o u g h

11

Paper Number 8 0 , P a c i f i c Ocean B i o l o g i c a l Survey Program, Smithsonian

-

I n s t i t u t i o n , Washington, D.C.

21 P r e s e n t a d d r e s s : Department of S y s t e m a t i c s and Ecology, The U n i v e r s i t y

-

of Kansas, Lawrence, Kansas 66045

3 1 P r e s e n t a d d r e s s : Department of Biology, C l i n c h V a l l e y C o l l e g e , Wise,

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V i r g i n i a 24293
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subsequent e x e c u t i v e o r d e r s have g i v e n primary j u r i s d i c t i o n over t h e a t o l l t o m i l i t a r y a g e n c i e s , f i r s t t o t h e Navy, l a t e r t o t h e U.S. A i r Force. P r e s e n t l y a J o i n t Task F o r c e h a s j u r i s d i c t i o n over a l l t h e a t o l l except f o r Sand I s l a n d , which is t h e s i t e of a U.S. Coast Guard LORAN s t a t i o n .

The a t o l l i s an u n i n c o r p o r a t e d t e r r i t o r y ( = p o s s e s s i o n ) of t h e United S t a t e s . T h i s i s d i s t i n g u i s h e d from an i n c o r p o r a t e d t e r r i t o r y

( = t e r r i t o r y ) i n t h a t i t i s " . . . t e r r i t o r y t o which t h e c o n s t i t u t i o n [of t h e United S t a t e s ] h a s n o t been e x p r e s s l y and f u l l y extended" (U.S.

Department of S t a t e , 1965: 9 ) .

Although t h e o c e a n i c r e g i o n i n which Johnston A t o l l l i e s i s r e l a - t i v e l y u n p r o d u c t i v e , l i f e i s abundant on t h e a t o l l i t s e l f . A t l e a s t h a l f a m i l l i o n s e a b i r d s u s e t h e a t o l l f o r r o o s t i n g and n e s t i n g . Most of t h e s e a r e of one s p e c i e s , Sooty Tern (Sterna

f u s c a t a ) ,

b u t t h e t o t a l known a v i f a u n a i s 56 s p e c i e s , i n c l u d i n g 12 r e g u l a r b r e e d e r s and half-a-dozen r e g u l a r m i g r a n t s . Other t e r r e s t r i a l forms a r e s c a r c e , and a r e l i m i t e d mainly t o i n t r o d u c e d s p e c i e s , i n c l u d i n g f i v e s p e c i e s each of mammals and r e p t i l e s , a l l of which were i n t r o d u c e d , a t l e a s t 87 s p e c i e s

of i n s e c t s , many of which were i n t r o d u c e d , and w e l l o v e r one hundred s p e c i e s of p l a n t s , o n l y t h r e e of which a r e n a t i v e .

The i n s h o r e marine b i o t a i s r i c h e r . To d a t e 194 s p e c i e s of

i n s h o r e f i s h e s have been r e c o r d e d , s e a t u r t l e s v i s i t t h e a t o l l r e g u l a r l y i n s m a l l numbers, p o r p o i s e s a r e o c c a s i o n a l l y s e e n o u t s i d e t h e l a g o o n , and i n 1968 and 1969 Hawaiian Monk S e a l s v i s i t e d t h e i s l a n d s f o r t h e f i r s t time so f a r a s i s known. T r o p i c a l marine i n v e r t e b r a t e s a r e abundant i n t h e lagoon.

M i l i t a r y o c c u p a t i o n and c o n s t r u c t i o n d u r i n g t h e p a s t 40 y e a r s have so d r a s t i c a l l y a l t e r e d t h e physiography of t h e i s l a n d s t h a t l i t t l e of t h e o r i g i n a l h a b i t a t t y p e remains. Breeding p o p u l a t i o n s of t h r e e of t h e 1 5 s e a b i r d s p e c i e s known t o have bred on t h e i s l a n d s were e l i m i n a t e d , w h i l e a few o t h e r s were a b l e t o i n c r e a s e through a d a p t a t i o n t o man-

made changes. For most b i r d s p e c i e s t h e a l t e r a t i o n of h a b i t a t and c o n t i n u e d d i s t u r b a n c e , sometimes through planned e f f o r t s t o move b i r d s t o l e s s c r i t i c a l a r e a s , sometimes through i g n o r a n t o r m a l i c i o u s p e r s e - c u t i o n , h a s r e s u l t e d i n s e v e r e l y d e c r e a s e d r o o s t i n g and n e s t i n g space and c o n s e q u e n t l y i n reduced p o p u l a t i o n s .

A s p a r t of i t s s t u d y of p o p u l a t i o n s , b r e e d i n g b i o l o g y , and

movements of s e a b i r d s of t h e c e n t r a l P a c i f i c Ocean, t h e P a c i f i c Ocean B i o l o g i c a l Survey Program ( h e r e a f t e r r e f e r r e d t o a s t h e POBSP) of t h e Smithsonian I n s t i t u t i o n , Washington, D.C., maintained one o r more b i o l o g i s t s on Sand I s l a n d , J o h n s t o n A t o l l almost c o n t i n u o u s l y from 7 J u l y 1963 u n t i l 9 September 1969 (Appendix Table 1 ) . Former POBSP employees have v i s i t e d t h e a t o l l t w i c e s i n c e 1969. B r i a n A . H a r r i n g t o n s t u d i e d Sooty Terns from 18 March t h r o u g h 3 J u n e 1971; A. Binion Amerson, J r . v i s i t e d Johnston 6-12 November 1973 f o r t h e O f f i c e of I n t e r n a t i o n a l and Environmental Programs, Smithsonian I n s t i t u t i o n , t o u p d a t e e c o l o g i c a l d a t a .

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Although primary emphasis was on t h e 12 s p e c i e s of b r e e d i n g s e a b i r d s , POBSP s t u d i e s a l s o i n c l u d e d a r t h r o p o d s , r e p t i l e s , mammals, and t e r r e s t r i a l p l a n t s . T h i s r e p o r t i s an a t t e m p t t o summarize t h e major r e s u l t s of t h e s e s t u d i e s and t o compile a comprehensive summary of o t h e r s c i e n t i f i c e f f o r t s made on Johnston A t o l l . The major t h r u s t of t h e r e p o r t i s i s l a n d - o r i e n t e d r a t h e r t h a n s p e c i e s - o r i e n t e d , and d i s c u s s i o n s p r e s e n t e d a r e p r i m a r i l y d e s c r i p t i v e r a t h e r than a n a l y t i c a l . Hopefully t h e d a t a p r e s e n t e d w i l l b e u s e f u l i n developing a d e t a i l e d a n a l y s i s of t h e c e n t r a l P a c i f i c ecosystem, and f o r comparison of p o p u l a t i o n and b r e e d i n g phenomena of t h e s e a b i r d s and o t h e r groups w i t h s i m i l a r d a t a from o t h e r i s l a n d s where t h e same s p e c i e s o c c u r .

T h i s r e p o r t i s based p r i m a r i l y on t h e f i e l d n o t e s and semi- monthly r e p o r t s made by t h e 29 POBSP p e r s o n n e l (Appendix T a b l e 1 ) who m a i n t a i n e d t h e Sand I s l a n d s t a t i o n . These voluminous d a t a a r e s t o r e d

i n t h e N a t i o n a l Museum of N a t u r a l H i s t o r y , Washington, D . C . T h i s f i n a l r e p o r t i s a combination of a m a n u s c r i p t by S h e l t o n and a t e c h n i c a l r e p o r t by Amerson (1973). Amerson's e c o l o g i c a l b a s e l i n e r e p o r t was used a s p a r t of a 1 0 May 1974 U.S. A i r F o r c e Environmental Impact

Statement concerning proposed d i s p o s a l of chemical h e r b i c i d e on Johnston ' A t o l l .

PHYSICAL ENVIRONbfENT

The p h y s i c a l c h a r a c t e r i s t i c s of J o h n s t o n A t o l l and i t s s u r r o u n d i n g w a t e r s a r e r e l a t i v e l y w e l l s t u d i e d . The f o l l o w i n g d e s c r i p t i o n s a r e based p r i m a r i l y on a c c o u n t s p u b l i s h e d by government a g e n c i e s o r by s c i e n t i s t s under government c o n t r a c t .

J o h n s t o n A t o l l l i e s between t h e l a t i t u d e s of 16°40'26" and 16"47'25" North and t h e l o n g i t u d e s of 169°24'15" and 169°33'58" West

(USNOO C h a r t 5356).

I s l a n d s

The two n a t u r a l i s l a n d s , Johnston (16'45'N x 169'32'W) and Sand (16'45'N x 169"301W), o r i g i n a l l y 46 and 1 0 a c r e s i n e x t e n t , l i e a m i l e and a h a l f a p a r t on t h e s o u t h e r n margin of t h e l a g o o n , which i s t h e s h a l l o w p o r t i o n of t h e r e e f p l a t f o r m ( F i g s . 2 and 3 ) . Summit Peak, n e a r t h e n o r t h w e s t end of Johnston I s l a n d , o r i g i n a l l y stood 48 f e e t above s e a l e v e l ( C h r i s t o p h e r s e n , 1931: 3 ) ( F i g s . 4 and 5 ) . The h i g h e s t p o i n t on Sand I s l a n d was and remains a b o u t 1 5 f e e t above s e a l e v e l . Both i s l a n d s were formed of beachrock--sand and g r a v e l cemented by calcium carbonate--and l o o s e s a n d , presumably wind and wave t r a n s p o r t e d m a t e r i a l (Emery, 1956, and A s h o r e , 1973).

From 1939 through 1942 c o n s t r u c t i o n f o r m i l i t a r y o p e r a t i o n s l e v e l e d J o h n s t o n I s l a n d and e n l a r g e d i t t o 211 a c r e s (Fig. 6 ) , and b u i l t a n o t h e r i s l e t about t h e s i z e of Sand I s l a n d and connected i t t o

Sand I s l a n d by a narrow causeway. These a d d i t i o n s were b u i l t mostly of c o r a l m a t e r i a l dredged from t h e lagoon i n deepening and l e n g t h e n i n g s h i p c h a n n e l s and s e a p l a n e l a n d i n g a r e a s . By 1944 Johnston I s l a n d had a

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Figure 2. Map of Johnston Atoll; adapted from Wennekens (1969) and A s h o r e (1973).

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Figur e 3. Looking northeast over Johnston and Sand Islands from 3,000 feet, 12 November 1935 (U.S. Nat.

Archives, R.G. 80 photograph).

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F i g u r e 4. The n o r t h e a s t end of J o h n s t o n I s l a n d a s i t appeared from t h e s o u t h i n J u l y 1923 (B.P. Bishop Museum photo by R. S. Palmer).

F i g u r e 5. J o h n s t o n I s l a n d , s e e n from t h e n o r t h a t 3,500 f e e t , 1 0 October 1939 (U,S. Nat. Archives, R.G. 8 0 photograph).

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6,100 f o o t runway, and b o t h i s l a n d s were v i r t u a l l y covered w i t h b u i l d i n g s , roadways, and gun emplacements. None of t h e o r i g i n a l s h o r e l i n e o r v e g e t a t i o n of Johnston I s l a n d remained.

The a i r s t r i p on Johnston was a g a i n e n l a r g e d i n 1951-52, and i n 1963-64 a d d i t i o n a l c o n s t r u c t i o n w i t h c o r a l dredged from t h e lagoon

e n l a r g e d Johnston I s l a a d t o 570 a c r e s ( F i g . 7 ) , w i t h a 9,000 f o o t runway, added a few a c r e s t o t h e a r t i f i c i a l p o r t i o n of Sand I s l a n d , and b u i l t two e n t i r e l y new i s l a n d s , Alcau (North) a t 16°45'52"N x 169"31103"W and Hikina ( E a s t ) a t 16°45'26"N x 169'29'19"W, of 24 and 17 a c r e s r e s p e c t - i v e l y , w i t h i n t h e lagoon (Bauer, 1965).

The p r e s e n t s u r f a c e s of J o h n s t o n , Alcau, and Hikina I s l a n d s , and t h e a r t i f i c i a l p o r t i o n of Sand I s l a n d , c o n s i s t of hard packed c o r a l m a t e r i a l r a n g i n g from sand t o cobble s i z e . B u i l d i n g s , a n t e n n a s , r o a d s , and (on J o h n s t o n o n l y ) runways and taxiways dominate t h e s e i s l a n d s . V e g e t a t i o n i s r e s t r i c t e d t o s p a r s e lawns, s c a t t e r e d bushes and t r e e s , and t h i n l y s c a t t e r e d weedy s p e c i e s on a r e a s t h a t a r e n o t f r e q u e n t l y d i s t u r b e d .

Although b u i l d i n g s f o r m e r l y occupied most of t h e o r i g i n a l p o r t i o n of Sand I s l a n d ( F i g s . 8 and 9 ) , t h e s e were removed i n t h e l a t e 1 9 5 0 ' s . A few c o n c r e t e f o u n d a t i o n s and gun emplacements remain. The only new s t r u c t u r e s added s i n c e t h e n a r e t h e LORAN-C t r a n s m i t t e r b u i l d i n g and t h e 625-foot t r a n s m i t t e r tower. Ground w i r e s r a d i a t e from t h e b a s e of t h e tower on o r j u s t below t h e s u r f a c e , and guywires extend t o c o n c r e t e p i l l a r s , most of them beyond t h e s h o r e s of t h e i s l a n d i n t h e lagoon

( F i g s . 1 0 and 1 1 ) . A roadway 3-eads t o t h e t r a n s m i t t e r b u i l d i n g from t h e causeway c o n n e c t i n g t h e two p o r t i o n s of t h e i s l a n d . Except f o r t h e s e s t r u c t u r e s , t h e s u r f a c e of t h i s o r i g i n a l i s l a n d i s approximately l i k e t h a t of b o t h J o h n s t o n and Sand I s l a n d s p r i o r t o t h e i r d i s t u r b a n c e . The i n t e r i o r i s covered w i t h deep, l o o s e c o r a l s a n d , bound by r o o t s of t h e g r a s s ,

Lepturus repens,

and p e r f o r a t e d by burrows of Wedge-tailed Shearwaters. A beachrock l a y e r i s exposed around most of t h e p e r i m e t e r of t h e i s l a n d .

Geology

Emery (1956) d e s c r i b e d t h e geology of J o h n s t o n I s l a n d based on i n f o r m a t i o n from 56 b o r i n g s f o r b u i l d i n g f o u n d a t i o n s , r a n g i n g t o 36 f e e t below mean low w a t e r , and from s i x w e l l s d r i l l e d t o d e p t h s r a n g i n g from 86 t o 1 9 1 f e e t below mean s e a l e v e l . None of t h e s e h o l e s reached non-calcareous r o c k . Two l a y e r s of beachrock were e n c o u n t e r e d , one above s e a l e v e l , and presumably c o r r e l a t e d w i t h t h e one s t i l l exposed on Sand I s l a n d b u t covered o r d e s t r o y e d on J o h n s t o n , and one a t 4.3 t o 6.4 f e e t below s e a l e v e l . T h i s lower l a y e r was a l s o found 8 f e e t below s e a l e v e l a l o n g b a s e s of t h e p a r a l l e l , l i n e a r a l g a l r e e f s t h a t extend between Johnston and Sand I s l a n d s . These r e e f s were thought t o r e s u l t from growth of c o r a l l i n e a l g a e on t h e o u t c r o p p i n g edges of submerged beachrock.

Below t h e beachrock t h e deeper p a r t s of t h e w e l l s showed a l t e r - n a t i n g sand, l o o s e c o r a l , and sand and c o r a l , w i t h l i t t l e c e r t a i n t y of

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Figure 6. Looking north over Johnston Island, 9 April 1942 (U.S. Nat.

Archives, R.G. 80 photograph).

16"45'

N

-1G044'

0 . 5 i i a u t i c a l Miles

16"43' 16g033' 169:32' 169P31'

Figure 7. Profile map of Johnstbn Island, Johnston Atoll, 1923, 1942, and 1964; adapted from A s h o r e (1973) and USNOO Chart No. 5356, 20 May 1963 and 23 December 1967.

(

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