MIGRATION

Migration of the Fork-tailed Flycatcher through southeastern .

New light on austral springmigration with an intriguingspeculation on North American vagrancy

H. T. Erickson

HEAPPEARANCE of vagrant Fork- in the highlands between the cities of CCURRENCEIN VI•OSA issporadic, tailed Flycatchers, Tyrannus sa- Rio de Janeiro and Silo Paulo. Several of and almost certainly represents vana savana Vieillot (formerly Musciv- her observations included aerial dis- transients near the eastern flank of their ora t. tyrannus), in the eastern United plays. They might have been nestingin migratory route. December and January Statesis regularly reported in American the area, which is within the tropics,but records for Caxambu' and Catas Altas Btrds. Monroe and Barron (1980) have there is no firm supportingevidence. are at elevations over 3000 feet, and in summarized North American records each instance birds were numerous and for the species.September and October While spendingseveral years in the appeared to be engagedin courtship sightingsaccount for more than one-half Brazilian state of , in the displays.They could have been on nest- of the total. This coincides with the village of Viqosa, located in the Rio ing territory, as this is mid-summer early stages of "spring" migration in Doce valley north of Rio de Janeiro, I Catas Altas is at the latitude of 20øS, southeastern Brazil. had occasion to observe the annual near . Caxambu' is near Large numbers of this highly migra- movementof thisvery conspicuousbird latitude 22øS in the Mantiqueira Range tory speciesspend the australwinter in (Erickson and Mumford, 1976). I also (Fig. 1). northern South America. Hundreds of made frequent trips to neighboring In late September and early October thousandshave been reported to roost states,often during migration. Observa- 1966an overland trip was made through in mangroves of Trinidad's Caroni tions suggest the presence of a well- northeastern Minas Gerais, eastern Swamp from May to October (ffrench, defined migration corridor and also the Bahia, through the states of Sergipe, 1966).A major southeastwardmigration possibilityof isolated breedingpopula- Alagoas and eastern and central Per- was observedin Venezuela in late Sep- tions within the tropics. nambuco west to Petrolandia on the Silo tember (McNeil and de Itriago, 1968). Francisco River. This is the time when This is the same subspecies which Most of this region is about 2000 feet T. savana appearsin numbersin central reaches the southern half of Brazil in in elevation and none is below 1000 feet. and western Minas Gerais. Only a single September, en route to breeding A few mountain ranges reach 4000 to individualwas seenduring the 2500mile grounds as far south as Rio Negro, 9000feet. Viqosais in the humidtropical journey, and it was in eastern Minas Argentina, (Meyer de Schauensee, forest zone, although the forest cover Gerais. Much of the route was well in- 1970)casually reaching the Falkland Is- itself has been largely removed. Open, land from the coastalplain, in generally lands (Cawkill and Hamilton, 1961). scrub-covered cerrado of the central open, savanna-typeterrain favored by The northern limit of their breeding Brazilian uplandsdominate central and the species.It would appearthat migra- range is not precisely known but is western Minas Gerais. tion is entirely west of the traversed thoughtto be wholly southof the Tropic The Fork-tailed Flycatchers arrive in area. of Capricorn (Zimmer, 1937). Pinto the southernpart of the state in Septem- In the latter part of October 1966sev- (1935) does not list the species in his ber, increasing:n number during Octo- eral days were spent in central Brazil account of birds collected in the eastern ber and November, when they become along the upper Xingu' River in north- half of the state of Bahia in an expedi- generally distributed in suitablehabitat, ern Mato Grosso. Heavy forests pre- tion lasting from November to April. It althoughthey are much less common or dominatebut substantialopen country •s alsoabsent from Berla's list of speci- absent in the extreme east. In December existswhich superficiallyat leastresem- mens collected in the coastal region of and Januarylocal populationsare pres- bles western Minas Gerais. No T Pernambuco, covering every month of ent at the higher elevations, but rarer savana were observed. the year (1946). Both locations are in elsewhere.The northward return migra- A month later they were similarly ab- extreme eastern Brazil. Mitchell (1957) tion evidently misses this area. Perti- sent from central Goifis state, around had only twelve sightingsfor southeast- nent records are listed in Table 1, by the city of Goifis, which is also west of ern Brazil over a four-year period. All months. In addition to these, many Minas Gerais. At the time they were occurredfrom Septemberto December other observations were made. common from Brasilia eastward.

136 American Birds, March 1982 EQUATC

AHI MATO

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Figure1. Mapof Brazilshowing a main migration route (arrow) of Fork-tailedFlycatchers to their sonthem breeding gronnds.Nambers in MinasGerais state correspond to the Map Key found in TableI.

Brasflia lies in the headwaters of three It is apparent that a major flight This supportsthe contentionthat north- of the nation'sprinciple river systems, passesthrough western Minas Gerais, erly vagrantsare indeed misdirected the Silo Francisco, Parana', and Ara- with the main body following the valley grants. guaiaoTocantinswhich flows northward of theupper Silo Francisco River and its to the mouth of the Amazon. As no T. tributaries. From the 15th to 22nd paral- ORK-TAILEDFLYCATCHERS aredis- savana were observedin the Araguaia- lels southlatitude, migration appearsto tinctive birds which are highly vis- Tocantins basin west of Brasflia at a channel between the 42nd and 50th ible in the open country they frequent timewhen they were common just to the meridians,centering on the 45th. Coas- The chancesare thus at least fair that a east,it would appearthe main flightwas tal plains are avoided. strong sampling of strays to North passingthrough the Silo Francisco The timingof thisflight coincides with America is sightedand reported. The drainage.Likewise, they seem to be the maximum sightings in North small, though persistent, number of uncommon in those smaller river basins America, i.e. September,October and North American sightingsemphasizes drainingdirectly eastwardto the At- November. AssumingTrinidad to be a the precisionof the migratoryinstinct lantic. The upper reachesof the Rio majorwintering location and a pointof To makea very pI:esumptiveguess, per- Doce and Rio Paraiba valleys pick up departurefor migrants,it is intriguingto hapsone individual in a millionmight be the flightto the south,and the Parana' note that Belo Horizonte, Brazil is ex- misdirected. [It may be, of course, that basin to the southwest, which includes actly the samedistance south as Boston there is a "mirror" migration among thecity of Lavrasand much of southern is north. Most North American records North American migrants wintering in Minas Gerais. center around southern New England. South America, moving southward in-

Volume36, Number 2 137 stead of northward in spring, but the Table 1. Some observationsof Tyrannus s. savana in Minas Gerais, Brazil. chances of detecting such vagrancy would be slim indeed]. Map Key Date Location Remarks My only record for Mato Grosso, where limited time was spent, was of a 2 Aug. 30, 1973 Viqosa Three birds, very early. I Sept. 9, 1960 Uba' First for the year. single bird at Cuiaba' on January 9, 2 Sept. 12, 1962 Vigosa First for the year. 1967. This, too, is in the Paraguay- 3 Sept. 18, 1962 20 +, aerial display. Pararia' river basin. Sick ½1959) found 4 Sept. 19, 1966 First for the year. them on the Goifis-Mato Grosso border 2 Oct. 5, 1959 Vigosa Two. in display. 5 Oct. 19, 1977 Common. "towards the end of 1943". Frisch and 6-7 Oct. 29, 1961 Belo Horizonte--Unai' Very common. Displays. Frisch (1964) list September recordsfor 2 Nov. 3, 1966 Vigosa Single. the western state of Rondonia and for !-8 Nov. 6, 1966 Uba'-- Several. the upper Xingu', where I failed to find 5 Nov. 18, 1959 Lavras Very common. them in October. It is possible that 9 Nov. 19, 1966 Tres Mafias Reservoir Common. 6-SP Nov. 21, 1960 Belo Horizonte•io Paulo Very common. another population migrates through 7 Nov. 26, 1966 Unai' A few present. the Amazon Basin in far western Brazil 7-6 Nov. 27, 1966 Unai'--Belo Horizonte Fairly common. in a more direct route south from the 8-1 Dec. 2, 1966 Juiz de Fora--Uba' Several. wintering grounds. 2 Dec. 8, 1961 Vigosa Several. l0 Dec. 9, 1962 F!orestal Very common. This leaves unresolved the migration II Dec. 15, 1966 Caxambu' Many present. route of the southeast Brazilian flight 12 Dec. 19, 1962 Rio Paraiba Valley Common. from the northern coast of South 2 Dec. 26, 1962 Viqosa One. Latest for location. America south to the 15th parallel. I 6 Jan. 4, 1963 Belo Hor•zonte One pair. have Belem records for late May 1980, 13 Jan. 12, 1963 Catas A!tas Numerous. Much display. 14 Feb. 2, 1963 One individual. apparentlyof winteringbirds. Snethlage 15 Feb. 11, 1963 Araxa' One. Latest record. (1914) lists specimensfrom the Tapajos River and from Maraj6 lsland and the city of Beirm, both near the mouth of October to late November. At this time FRISCH, S. and J.D. FRISCH. 1964. the Amazon. Dates were not given. it appearsto be scarce in adjacent parts Aves Brasileiras. Irmios Vitale S/A. Silo Paulo. Some could have been migrants. Zim- of the Amazon Basin at the same MEYER DE SCHAUNSEE, R. 1970. A mer (1937) lists specimens from Re- latitude. It is also absent from the lower guide to the birds of South America. manso, Bahia. Significantly, Remanso reaches of smaller rivers flowing di- Livingston Pub. Co., Wynnewood, Pa. is on the Silo Francisco River where it rectly east into the Atlantic. No evi- MCNEIL, R. and M. CARRERA DE IT- bends sharply southward, some 450 dence was found for a return migration RIAGO. 1968. Fat deposition in the Scissor-tailed Flycatcher (Muscivora t. miles from its mouth, at the same meri- through this area. tyrannus) and the Small-billed E!aenia dian, the 42rid, as my easternmost rec- Breeding populations may exist (Elaenia parvirostris) during the austral ord. Evidently they move southeast within the tropics of southeastBrazil at migratory period in northern Vene- from the wintering grounds to the Silo higher elevations. zuela. Canadian Jour. of Zoology 46:123-128. Franciscovalley, possibly reachingit at MITCHELL, M.H. 1957. Observations on about latitude 10øS, then follow the val- birds of Southeastern Brazil. Univ. of ley upstream passingthrough that part Toronto Press. of southeastern Brazil mentioned MONROE, B.L. and A. BARRON. 1980. above. This route would also account The Fork-tailed Flycatcher in North America. Am. Birds 34:842-845. for their absence near the coast. PINTO, O. 1935. Aves da Bahia. Revista Sick ½1958) did not list them for do Museu Paulista. Tomo XIX. Brasflia in late April and early May. My SICK, H. 1958. Resultados de uma excur- latest record is for February I l, in west- silo ornitologica do Museu Nacional a Brasflia, novo Distrito Federal, Goiis, central Minas Gerais. Assuming this is coma descrigio de um novo repre- part of the same population that winters sentante de Scytalopus. Boletim do LITERATURE CITED in Trinidad there is a two-to-three Museu Nacional, Rio de Janeiro. Nova month interval between departure from Serie. Zoologia No. 185. their breeding territory and arrival on BERLA, H.F. 1946. Lista das aves col- -- 1959. Tukani. Burke Pub. Co. Ltd. ecionadas em Pernambuco, com des- London. the wintering grounds. Few records ap- crigio de uma subesprcie N., de um SNETHLAGE, E. 1914. Catalogo das pear in the literature to accountfor their a!rtipo e notas de campo. Boletim do Aves Amazonicas. Boletim do Museu whereabouts at this time. Museu Nacional Rio de Janeiro, Nova Goeldi. Tomo VIll. Serie Zoologia N.65. ZIMMER, J.T. 1937. Studies of Peruvian CAWKILL, E.M. and J.E. HAMILTON. SUMMARY birds, 27. Notes on the genera Musci- 1961. The birds of the Falkland Islands. vora, Tyrannus, Empidonomus, and Ibis 103:1-27. $irystes with further notes on Knipole- HEFORK-TAILED FLYCATCHER, Ty- ERICKSON, H.T. and RUSSEL E. gus. Amer. Mus. Novit. No. 962. pp. 1- •a•rannus savana savana, migrates MUMFORD. 1976. Notes on birds of 28. southward in large numbers through the the Vigosa, Brazil region. Purdue Univ. AES Station Bull. 131. Silo Francisco River valley in western ffRENCH, R.P. 1966. Utilization of man- --Horticulture Department, Minas Gerais, Brazil from Septemberto groves by birds in Trinidad. Ibis Purdue University, December, probably peaking from late 108:423-424. W. Lafayette, Ind. 47907.

138 American Birds, March 1982