Ecology of the Maryland Yellow-Throat, and Its Relatives

I 2} 7 tributed over most of North and'Central America and part of South America, from sea level to about 6000 feet, and exhibits considerable diversity in extent and intensity of color areas, especially in the males.These color values, together with slight structural characters, permit of the forms being arranged in nine natural geographical and evolutional groups.Without violence, the genera Jkricroliffea (Santo Domingo) and ]'eretristis (Cuba) may both be included in Geothlydpis.The former, G. 2palustris, is a tropical G. a•ilis, and the latter, G. fornsi and fernandinaz, are ancestral representatives of GeothIyi)is, and but slightly specialized.dValural ffrauzps of Geothlyzpis as shown firinct•aIly in the 2kZales.x.No black, grayish above, yel-l fornst', Cubaß low beneath.fernandz'ncv, Cuba. 2. }lead, neck and breast slaty, •' short wings, long tail, •-4 •aluslris, Santo Domingo.slightly slaty.L 3. Head• neck and breast slaty fa•t.lz.s• ' British America.with slight black areas, long ß • tol•nz'el, Western U.S. wings, short tall, • nearly •t'laclel•[a, Eastern U.S. similar.'a.strongly 'brachidaclyla, Northeastern U.S. marked, lrœc•as, Eastern U.S. 4. Pale slaty, and c o n t i-• roscoe, Southeastern U.S. blackface bands,' nental.occidenlalz's, Western U.S. melano•3s Northeastern Mexico.absent in •. b. less def-,'rostrala, New Providence Id., Bahamas.inite, in-• tanneri, Abaco Id., Bahamas.sular..coryœ,Eleuthera Id., Bahamas. 5. Yellow and black head bands •beldln[i, Lower California.rich coloration, • without4 ½avovelala, Southern Mexico.black.•dqavœce•s, Southeastern Mexico.• cucullala •, Southern Mexico.6. Black face band, broad and[s•eclosa •, Southern Mexico.short, very rich coloration,-• baitall, Western Central America.• without black.[ chert'•uensis, Northern Colombia.[ setnt•lava, Colombia.7. Facial black short and nar-(cefut'noclt'alt5, Northern S. America.row, slaty crown patch, rich• aurt'culart•, Peru.coloration, • without black.(velala, Brazil.Subgenus Od•oror•tis.• Slight slaty crown patchß vot.xY" ] 1900 PALMER, The Maryland Yellow-throat.l sular.( coryi, Eleuthera Id., Bahamas. 5. Yellow and black head bands, f beldingi, Lower California.rich coloration, § without< flavovelata, Southern Mexico.black.(Zaviceps, Southeastern Mexico.(cucullata, Southern Mexico.6. Black face band, broad and � 1 speciosa 2 , Southern Mexico.short, very rich coloration, bairdi, Western Central America.§ without black.cheriquensis, Northern Colombia.\ semiflava, Colombia.7. Facial black short and nar-(quinoctialis, Northern S. America.row, slaty crown patch, rich auricularis, Peru, coloration, § without black.( velata, Brazil. 1 Subgenus Oporornis.° Slight slaty crown patch.[Auk 218 P^L.•IER, T,•e Maryland Yellow-t,•roat.[July 8. Slight facial black, short •ral•ht', Northeastern Mexico.wings, lo.ng tail, pale col-•ol•oce•,Sala, Mexico.oration, grayish dorsum • q •al•ebralt's, Mexico.without black.Subgenus ] cant'nuc•Sa, Guatemala.Chamcet•l),]3•.• •'clerot•, Costa Rica.9. Short and broad facial black, r slight slaty crown band, i formosa •, Southeastern U.S. sexes nearly similar.[ In groups 4, 5, 6 and 7 there is a sequence of structure and color values, largely geographical and not present in the other groups.Seemingly, group 8 continues the sequence frown group 7.The intense, rich coloration of group 6 evidences the values of a moist tropical habitat.The short boreal summer residence of group 3 has hardly effected their color values.The habitats 2, 2'0 PALMER• The 3•raryland Yellow-lhroaL [-Auk 1July changes as geological influences have affected the topography, and, therefore, we might expect to find a great variation among the characters most likely to be affected.As these influences have acted gradually through a long series of years upon somewhat different material, it follows that results will be different, according to the distances between the geographical areas examined, because the influences are more dominant at one point than at some other.The forms here recognized and their values and distributions are as follows: Geothlypis trichas AND SUBSPECIES.Adult •' in spring: Above olivaceous broxvn, darker on wings and tail; beneath yellowish, stronger and brighter on throat, breast, and under tail-coverts; sides of breast ollvaceous; forehead and face black, bordered posteriorly by ashy white; bill blackish, deeper than broad, tapering to a point; wings short and rounded, outer primary shorter than next; tail shorter than wing, well rounded; feet flesh colored; tarsus longer than midtoe, lateral toes nearly equal and as long as midtoe minus claw.Adult • in spring: Similar to male but smaller, less richly colored and without black; a faint Ioral stripe; ear-coverts darker than grayish face.Immature and winter adults: Similar to summer specimens of the same sex, but with the face markings less strongly defined and less extensive; coloration richer with a browner dotsurn.The Subs•ecies.Geothlypis trichas trichas.MARYLAND YELLOW-THROAT.Turdus trt'chas Li•-,'Nmus, Syst.Nat.ed.x2, x776, 293.Type locality, Maryland.Adult •' in summer: Smallest; above olivaceous, brownish on pileurn; throat, breast and under tail-coverts lemon yellow; sides of breast grayish olive; facial black restricted, narrow on forehead; outer primary shorter than the 6th; •ving, 50-54 mm.; tail, 48-52 min.;culmen, 9-,0 ram.; tarsus, 2I-23 min.Adult •: Smaller than •', relatively stouter bill; yellow of throat paler, restricted, sometimes absent.