Descriptions of new birds from the Tres Marias Islands, western Mexico

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BIOLOGICAL SOCIETY OF WASHINGTON

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DESCRIPTIONS OF NEW ^BIRDS FROM THE TRES MARIAS _ISLANDS, WESTERN MEXICO.

BY

E. \V.

NELSON.

The _specimens upon ^which

^the present

paper

^is

based were obtained by myself and my

assistant,

Mr.

E. A.

Goldman, on ^the Tres Marias

_Islands, off the

west

coast of

Mexico, during May,

1897.

Our

visitthere

was

a

continuation

of the

work

carried

on

in

Mexico by

the Biological

Survey

^ofthe

Department

of Agri- culture.

Special ^efforts

were made

to secureseries of the resident

land

birds, in

which we were

_quite successful.

The _study

of these series,in

connection with our

collection

from

the

adjacent main- land during

^the

same

season, indicates that

most

ofthe resident

land

birds ofthe _islands,

not already

described, ^differin a

more

orless

marked degree from

^theirnearest

mainland

relatives.

In most

cases the island birds

cannot be considered more than

_geo- graphical^races,

although

^a

few

differ sufficiently ^to

be

treated as species.

Not

a single species

has been found on

the islands

which

has not a closely related

form on

the

mainland. The

bird

fauna

as a

whole

will

be

treated in detailin a

paper now

in

course

of preparation.

Previous work on the Tres Marias maybe

briefly

summarized

as follows:

In 1865-1867

the

group was

^{visited three}

^times by Colonel

A.J.

Grayson, who made

extensivecollectionsofbirdsfor the

Smithsonian

Institution.

From

these collections a

number

of

new

_species

and

_subspecies

have been

described atvarious

times by

Baird, Cassin,

Lawrence, and Ridgway. ^In

addition,

Von

2—

Biol Soc. Wash.,Vol. XII,1898 (5)

6 Nelson — _{New Birds from}

Western Mexico.

Madarasz has

described a Vireo

from

a collection

made

there in

1881 by ^Mr.

^{A. Forrer.}

^Mr. Xantus

is

supposed

^to

have

visited the islands

during

his stay

on

the

west

coast of

Mexico, but we have no

definite

information

in regard ^{to his}trip.

I

am indebted

to Dr.C.

Hart Merriam, Chief

^ofthe Biological

Survey,

^forthe

opportunity

^to

prepare

the present paper.

My

thanks

are

due

also to

Mr. Robert Ridgway,

Curator,

and

Dr.

Chas. W. _Richmond,

Assistant Curator, of

Birds

in

the

U. 8.

National Museum,

^for

^continued

^favors

during

the progress of

my ^{work on Mexican}

^birds.

All ofthe birds

described below, except

^the

Magdalena Wren, which seemed

to

be

restricted to

Magdalena

Island,

were taken on Maria Madre

_Island,

and probably occur on

the other islands also.

All

measurements

areinmillimeters.

Columba

flavirostris

madrensis

_subsp.

now

Tres Marias_Pigeon.

Type No. 156698,^IT.S.Nat. Mus.,Biological SurveyColl., tf ad.,Maria

Madre

_{Island, Mexico,}

May

13, 1897. Collected by ^E.

W.

Nelson

and

E. A.

Goldman.

Description.

—

_{Differs fromtypical} C. flavirostrisin

somewhat

larger size;

decidedlylargerand _longerbill

and

generally palercolors; lowerborder of greater

wing

^coverts broadlymargined with white^{as in} Columba gym- nophthalma.

Dimensions

of type: wing, 209; tail, 138; culmen, 17;

tarsus, ^26.

Average measurements^ofColumbaflavirostris.

— _$

_(4specimens): wing, 195.5; tail, 123.5; culmen, 13.7; tarsus, 24.7.

9

(3 specimens): wing, 193; ^tail, 120.6; culmen, 14.1; tarsus, 25.3.

Average measurements^{of C.} flavirostris madrensis.

—

<$ (4 specimens)^: wing, 202.7; tail, 129; culmen, 15.7; tarsus, ^27.1. 9 (3 specimens):

wing, ^201; tail, 127; culmen, 16.6; tarsus, ^26.3.

A _single specimen from ^{the islands lacks the} white margins on ^the greater wing^enverts, but hasallthe other characters oftheinsular_race, suchasthe_largehill

and

_palecolors. Thisistheonly one

among

^adozen

in- more specimens

examined

which lackedthis marking.

The

mainland yellow-billed pigeon not infrequentlyhasa narrow margin^of whiteon the borders of the greater coverts,butI

have

never seen one in which thischaracterissostrikingason the ordinary island^birds.

Leptotila capitalis subsp.

now

TresMarias Dove.

Type No. 156709, U. S. Nat. Mus., Biological Survey Coll., ad. _tf, Maria

Madre

Island, Mexico,

May

^{6, 1897. Collected}

by

^E.

W.

Nelson

and

E. A.

Goldman.

Descriptionoftype.

—

_Forehead,

_{and crown}

to line between middle of

orbits, pale

creamy

^drab, shading abruptly into the purplish iridescence which overlies remainder of crown

and

back of neck. This _purplish iridescence onthe neck ends _{abruptlyjust in} frontof shoulders,andis

bordered

by

^anarrow

band

of feathers tippedwith_greenishiridescence.

Entire dorsalsurface, includingwings

and

middle_{pair of} tailfeathers,

brown

with anolivewash, except on^tail

and

_uppertailcoverts. Throat distinctlywhitish; remainderoflowersideofneck

and

thenceback over chest delicate

creamy

^lilac;

abdomen and

undertail coverts white with a_pale

wash

_{of huffy}

brown

on_{edges of}

some

ofthefeathers. Flanksdull huffy

brown

; tail feathers, except middle pair, blackish tipped with white —thistipping broadest

on

outer pair of feathers^; under

wing

^coverts

and

axillarspale cinnamon. Dimensionsof type: wing, 152; tail, 109;

culmen, ^18.5; tarsus, ^:;:;.

Averages^of Leptotila fulvlventrisbrachyptera.

— _$

_{(5 specimens)}: wing, 147.8; tail, 108.8; culmen, _16; tarsus, 31.3. $ (3 specimens): wing, 144 3; tail, 104.6; culmen, 15.6; tarsus, 30.6.

Averages ^{of L.} capitalis.

— $

(5 specimens): wing, 152.5; tail, 110.6;

culmen, 17.9; tarsus, 322.

$

(3 specimens): wing, 151.6; tail, 107;

culmen, 18.8; tarsus, 30.6.

This _species can hedistinguished ^at once from its nearest mainland relatives, P. fulvlventris said ^P. fulvlventris brachyptera,

by

^{its palercolors}

and

_largerbill. Stragglers of typicalbrachyptera occurontheislands, as

shown by

^a specimen obtained^there

by

^Col. Grayson,

now

in theNa- tional

Museum.

Thisspecimen ^isidenticalwiththe

mainland

bird

and shows

^nosign ofapproach^to the insular_species.

Buteo

borealis

fumosus

_subsp.

now

Tres Marias Red-tailed

Hawk.

Type ^No. 156714, U. S. Nat. Mus., _Biological Survey Coll., ad. _<j\

Maria

Madre

_{Island,Mexico,}

May

6, 1897. Collected

by

^E.

W.

Nelson

and

E. A.

Goldman.

Description.

—

_Entire

_{head and}

neck _nearlyuniform

smoky

brown, with scarcely a^traceof_lightermarkings on throat or chin.

Back and

wings blackish

brown;

^breast

and

remainder of lower _surface, except neck, heavily

marked

withdull rusty,

smoky

^brown,

^and

^dullwhitish or buffy^; no_{sign oflighter}areaon_breast; the markings

on

ventral surface arein the form of indistinct barrings

which

are most clearly defined

on

the tibia. Dimensionsoftype^: wing, 375; tail,206; culmen, 26; tarsus,^81.

Averages^{of Buteob.} socorroensls.

—

_tf

(2 specimens)^: wing, 387.5; tail, 207.5; culmen, 25; _tarsus, ^80.

$

(1 specimen): wing, 425; ^tail, 221;

culmen, ³⁰; tarsus, ^86.

Averages ^{of B. borealis} fumosus.

—

_{cT (3} specimens): wing, 373.3; tail, 207.3; culmen, 26; tarsus, ^81.3. 9 (1specimen): wing, 412; tail, 214;

culmen,³⁰; tarsus, ^84.

The

Tres Marias form is darker

and more

_uniformly

marked

_below,

and

lacks the _lighter areas

on

throat

and

breast that are foundin B.

borealis socorroensls.

On

the dorsal surface fumosus^isreadily distinguish- ablefromsocorroenslsbytheuniformly

smoky brown

^head

and

_neck,the

8 Nelson — _{New Birds from} Western Mexico.

rustyedgings^totheneck

and wing

^{feathersofthelatterbird} being^en.

tirely absent. Curiously enough,although ^{the Tres} Marias Islands are only aboutone-fifth as farfromthe coastasSocorro _Island, yettheTres Marias raceis

more

distinctfromB. borealiscalurusthanissocorroensis.

Polyborus cheriway

pallidussubsp. nov. TresMariasCaracara.

TypeNo. _156715,U.S. Nat. Mus., Biological SurveyColl.,

J

¹ad.,Maria

Madre

_{Island, Mexico,}

May

3, 1897. Collected

by

^E.

W.

Nelson

and

E.A.

Goldman.

Description.

—

_General

pattern of colorationas in P. cheriway,but

much

paler or lighterbrown.

The

darkest adultfrom theislandsis

somewhat

palerthanthe_palestadultfromthemainland in the considerableseries Ihave examined.

The same

proportionately palercolors prevailon im- maturebirdsfromthe islands.

The

terminal black

band

onthetailof the island bird averages narrower,

and

theotherdarkbarsonthetailare fainter.

The

_lightand dark markings

on

backatbase ofneckarein the formof regular bars instead of beingbrokenintoaroughly

wavy

pattern

by

^{the ovalform of}the black areas on the featliers,as in specimens^of cheriwayfromthemainlandofMexico.

The

_{wing, tail,}

and

tarsusaver- age shorter than in cheriway of the

Mexican

mainland, ^bill about the same. Dimensions_{of type}: wing, 370; tail, 198; culmen, 32; tarsus,^86- Averagesof Polyborus cheriway (frommainlandof Mexico).

—

_{r^ (4speci-}

mens)^: wing, 392; ^tail, 208.7; culmen, 32.5; tarsus, 90.7. 9 (2speci- mens)^: wing, 396.5; tail, 217.5; culmen,33.5; tarsus, ^89.

Averages^{of P.}cheriwaypallidus.

—

_{tf (4} specimens): wing, 370.7; tail, 194; culmen, ³²; tarsus, 86.5.

$

(4specimens) ^: wing, 386.5; tail,205;

culmen,^32.7; tarsus,^88.

A

specimen from ^themainland _adjacent to the TresMarias groupap- proximates^theislandform,

and

aseriesmight prove^{the birds}fromthat district tobeintermediate.

Trogon ambiguus goldmani

subsp. nov.

Goldman's

Trogon.

Type No. 156752, U. S. Nat, Mus., Biological Survey Coll., ad. _cT, Maria

Madre

Island,Mexico,

May

10, L897. Collectedby ^{E. YV.} Nelson andE. A.

Goldman.

Description.

—

Malesdecidedly greenerabove than_typicalambiguus, with very^littleofthecopperyiridescencecharacteristicof thelatter. Females and

young

^differstill more, ^theirbacks beingdecidedlyashy

and

_having

much

paler rufouson middle tail feathers; exposed parts of _scapulars, tertiaries,

and wing

coverts gray, mottled with _fine,wavy, ^blacklines with _slightindicationof the

brown which

formsthe

main

colorof these feathers inambiguusproper; ^colors oflower parts decidedly paler. In size the two forms differ but little. Dimensions oftype^: wing, 128;

tail, 148; culmen, 20; tarsus, 17.

Averagesof Trogon ambiguus.

—

(^(4specimens)^: wing, ^{131; tail,}161.2;

culmen, 19.5; tarsus, ^16.7.

9

(1specimen) ^: wing, 127; ^tail, 170; ^cul-

men,

^18.5; tarsus, ^17.

Averages ^{of T.} ambiguus goldmani.

—

_{-f (4 specimens)}: wing, ^130.7;

tail, 153.2 : culmen, ^19.7; tarsus, ^17. $ CI specimen)^: wing, 134; tail, 167; culmen, 19; tarsus, ^IS.

Nyctidrornus

albicollis insularis subsp. nov. Tres Marias Parauque.

Type No. _156765, U. S. Nat, Mus., Biological Survey Coll., ad. _cT>

-Maria

Madre

Island,Mexico,

May

JO, 1S97. Collected by ^E.

W.

Nelson

and

E. A.

Goldman.

Description.

— _The

_{islandbirdscan be} distinguishedfromN.albicollis,of the_adjacentmainland,

by

uniformly duller,

more

_grayish

brown

colors of entire dorsalsurfaceand broader transverse dark 'bars

on

lower sur- face,especially

on abdomen and

flanks.

The culmen and

tarsusarerel- atively shorter

and

wings

and

taillonger. Dimensions oftype^: wing, 173; tail, 169; culmen, 11 ; tarsus, ^26.

Averages of Nyctidrornus ^albicollis (from mainland of Mexico).

— _$

₍₅

specimens): wing, 158.4; tail, 146.6; culmen, 11.2; tarsus, 26.5.

$

(5

specimens): wing, 152.6; tail, 136; culmen, 11; tarsus, 25.9.

Averages^{of N.alb}',<<,His insularis.

—

_{c? (5specimens)}: wing,^170.6; tail, 162.4; culmen, 10.9; tarsus, 25.9. 9 (5specimens)^: wing, 168.4; tail, 154.4; culmen,11.6; tarsus, 25.8.

A

notablefeature of _insularis,

shown

intheseries before me, ^isitsre-

markable constancyof coloration

compared

^{with the}

amount

of variation inthe_large

number

ofmainland specimens examined.

The

latter

show

awide range^ofcolorfrom_grayishto rufous.

A

_{single specimen} in the islandseries hasaslight rufous shading,but agrees with the others in size. Inthemainlandseriesaspecimen from Ixtapa,Jalisco, ^iscolored like _insularis, but _agrees with other birds from the

same

_region in its

smallersize.

Myiopagis

placens

minimus

_subsp. nov. Little

Green

Flycatcher.

Type No. 156817, U. ^S.Nat. Mus.,BiologicalSurvey^{Coll., ad.} -f,

Maria Madre

Island, Mexico,

May

10, 1807. Collected

by

^E.

W.

Nelson

and

E. A.

Goldman.

Description.

—

_{Similar to M. placens,} but grayer, especiallyabout head

and

neck; top of

head and

neck_lighter than rest of dorsal surface in- stead of darker,^{as in} the mainland form.

The

island form _averages smaller than true placens. Dimensions of type: wing, ^64.5; tail, 66;

culmen, 12; tarsus, ^19.5.

Averages of Myiopagis placens.

— _{$ and 9}

_{(8 specimens)}: wing, ^68.2;

tail, 65.8; culmen, 11.2; tarsus, ^19.1.

Averages ^{of M.} placens minimus.

— _$

_(? specimens): wing, 64.9; tail, 64.8; culmen, 11.8; tarsus, ^19.4. ? (5specimens)^: wing,65.5; tail,63;

culmen, 11.6; tarsus, ^19.2.

In theNational

Museum

isa typicalspecimen ^ofplacens taken onthe TresMarias

by

^Col. Grayson,

showing

^{thatitoccursthereasa}straggler.

10 Nelson — New Birds from ^Western

^Mexico.

Cardiualis cardinalis mariaesubsp. nov. TresMaria Cardinal.

TypeNo. 1561)07,U.S.Nat. Mus., BiologicalSurveyColl., ad. rj\Maria

Madre

Island, Mexico,

May

3, 1897. Collected

by

^E.

W.

Nelson and E. A.

Goldman.

Description.

—

Males

most

like tbose ofC. cardinalis igneus,but red of under_partsdeeper and richer, lacking tbepinkishsuffusion notable in igneus; colorofbackalso richer,

and

featherslessedged withgray.

The

females of the

two

forms are

more

distinct thanthe males. ^('.

mariaehas a_largewhitish throat_area,

and

theentire

abdomen

^iswhitish, thus confining the

main

huffy area of lower _{parts to a} broad _pectoral band.

The

billis

more

swollen; the

wing

^islonger

and

tailshorterthan in_igneus. Dimensionsof type: wing, 101; tail, 103; culmen,20; tarsus, 29.

Averages ^{of Cardinalis c.} igneus.

—

_cj (4 specimens): wing,^94.5; tail, 106; culmen,20; tarsus, ^26.6.

9

(3specimens)^: wing, 91.6; tail,104.3;

culmen, 20; tarsus, 26.8.

Averages ^{of C. c. mariae.}

— _$

₍₄ specimens): wing, 97.7; tail, 98.7;

culmen, 20.5; tarsus, 28.9.

9

⁽⁴ specimens): wing, 91.7; tail, 89.7;

culmen, 19.9; tarsus, 28.2.

Vireo hypochryseus

^soididussubsp. nov. Tres MariasYireo.

Type No. 156898,^{IT. S.}Nat. Mus., Biological SurveyColl.,ad.

J

¹,Maria

Madre

Island, Mexico,

May

13, 1897. Collected

by

^E.

W.

Nelson

and

E. A.

Goldman.

Description.

—

_Differsfrom V.hypochryseusin duller,

more

olivegreen on dorsal surface,

and

_dingier,

more

_{greenishyellow}under_parts.

The

bill isdarker horn colorand_largerthanintrue hypochryseus. Dimensionsof type: wing, 66; tail, 61; culmen, 13; tarsus, ^21.

Averages ^of Vireo hypochryseus.

— _$

₍₅ specimens): wing, 63.4; tail, 57.8; culmen, 12.4; tarsus, ^19.5.

9

(2specimens)^: wing, ^63; tail,55.5;

culmen, 12; tarsus, ^20.

Averages ^{of V.} hypochryseus sordidus.

—

-tf (7 specimens): wing, 67.3;

tail, 60.3; culmen, 13.3; tarsus, ^21. 9 (3 specimens): wing,66.3; tail, 60.7; culmen, 12.7; tarsus, ^21.1.

Melanotis

caerulescens longirostiis subsp. nov. Tres Marias Blue Mockingbird.

TypeNo. _156923,IT. S. Nat. Mus., BiologicalSurveyColl.,ad _tf,Maria

Madre

Island, Mexico,

May

4, 1897. Collected

by

^E.

W.

Nelson

and

E. A.

Goldman.

Description oftype.

—

_General color dull slaty bluewith _{a grayish}cast;

top ofhead

and

allofneck andbreast palerthanrestof

body

^{; remainder} of lower_{parts dull}grayish blue(becoming

smoky

^{bluish in}

some

_speci- mens); back, rump, scapulars,

and wing

^{coverts dull} slaty blue.

Two

centraltail feathers

and

outer

web

of other rectrices

same

asback; rest

oftail dullblack; lores,ear_coverts,

and

forepart ofchinblack.

Dimen-

sionsof type: wing, ^{101; tail,} 104; culmen, 29; tarsus, ^32.

Averages of Melanotiscserulescens.

—

_{tf (4} specimens): wing,115.5; ^tail, 125.5; culmen, ^24.9; tarsus, 31.2.

$

(1specimen)^: wing, 106^; tail,111;

culmen, 24.5; tarsus,^29.

Averages^ofM. cserulescens longirostris.

—

_rf

(3 specimens) ^: wing,104.6;

tail, 105; culmen, 29; tarsus, 30.6. 9 (1 specimen): wing, 108; tail,

102; culmen, 29; tarsus, ^32.

The

_{grayercolors,}smallersize,

and

_largerbillarethe

main

_pointsdis- tinguishing^this form from_typicalcserulescens.

Thryothorus

^lawrencii

magdalenae

subsp.

now _Magdalena

Island Wren.

Type^No. 156943, U. S. Nat. Mus., Biological SurveyColl., ad.

$, Mag-

dalena _Island, Mexico,

May

28, 1897. Collected

by

^E.

W.

Nelson

and

E. A.

Goldman.

Descriptionoftype.

— Back warm umber brown

witha_slightgrayishwash;

top ofhead

and

neck_deeper,purer rufescentthan back;

rump ^and

upper

tailcoverts_lighter, brighter rufescentthan back; wings

and

middletail feathersrufous

brown

; tail irregularlybarredwith blackish

brown and

whitish, the ^{latter color}

more

or less heavilyshaded with dull rufous

brown

; a distinctwhitesupra-loral stripefrombase ofbillto nape^{; sides} of head

and

neckindistinctly

marked

with blackish lines; chin, throat, breast,and middleof

abdomen

white; ^sidesof breast

and

flanks reddish

brown;

^{undertail coverts} whitish witha shaft line

and

_spot(or bar)of blackish In-own near_tips. Dimensionsof type: wing, ^{.55; tail,} 55; ^cul-

men,

16.5; tarsus,^21.

Average^of3adultmalesof Thryothorus^lawrencii.

— _Wing,

60; tail,55.6;

culmen, 17.2; tarsus, ^22.

Thisform combinescertain charactersof_typical T. felixwith those of T. lawrencii.

The

rufousonthe

crown and

_napeiseven deeper thanⁱⁿ typicalfelix, whilethewhite lower_partsareas intruelawrencii.

Compared

^withaspecimen^offelixfrom Ometepec, Guerrero, believed tobe _typical,magdalense has a pure white area covering

most

of lower parts in place of therichrufousof_felix.

The

rufousofthe flanksispaler;

undertailcovertslessbarred;

crown and rump

nearly the

same

shadeof rufous; backa little grayer; ^sidesofhead

much

less heavily streaked with black.

From

lawrenciiit

may

^be distinguished

by

^its

much

richer colored or

more

rufousupperparts,

by somewhat

^heavierdarkstreakingontheside ofthehead

and

neck,

and by

^{the richer}

wash

of rufous

on

theflanks.