AN ANALYSIS OF UNOSUAL FLIGHTS OF NEOTROPICAL MIGRANTS TO NORTHEASTERN NORTH AMERICA 
Figure 2. Approximate locations and dates of first appearances of early Neotropical migrants and vagrants in the northeastern Unit- 
ed States and Atlantic Canada, early April 2009, with mainland Nova Scotia and southern New Brunswick as inserts. Blue dots are In- 
digo Buntings and red dots are Summer Tanagers. In alphabetical order, the abbreviations (banding codes) for other species are: 
BLGR, Blue Grosbeak; COYE, Common Yellowthroat; EAKl, Eastern Kingbird; GRAC, Gray Catbird; HOWA, Hooded Warbler; KEWA, Ken- 
tucky Warbler; LOWA, Louisiana Waterthrush; PROW, Prothonotary Warbler; PUMA, Purple Martin; RBGR, Rose-breasted Grosbeak; 
SCTA, Scarlet Tanager; WEVI, White-eyed Vireo; WEWA, Worm-eating Warbler; YTVI, Yellow-throated Vireo. 
viewed many early examples of wind-assisted 
spring migration. Gunn and Crocker (1951) 
used weather patterns, including maps of 
fronts and wind directions, to analyze a very 
early fallout (4-7 April 1947) of overshooting 
migrants and vagrants in the Great Lakes re- 
gion and elsewhere. They concluded: “It 
seems most likely that many of the birds be- 
gan their flight from the Mississippi valley 
south of the southern border of Tennessee.” 
Spring overshoots in the northeastern Unit- 
ed States and Atlantic Canada have also been 
connected to meteorological circumstances. In 
a pioneering essay, Bagg (1956) inferred from a 
weather map for the night of 16 April 1956, 
which showed a low-pressure system centered 
near the central Great Lakes with a cold front 
moving towards the East, that a “strong north- 
eastward flow of tropical air from the Gulf to 
Massachusetts [...] produced [...] from Rhode 
Island through eastern Massachusetts to Maine 
and Nova Scotia, an outstanding incursion of 
straggler Indigo Buntings, Summer Tanagers, 
and Rose-breasted Grosbeaks.” Among more 
recent examples, “an unprecedented flight of 
Blue Grosbeaks and Indigo Buntings [...] and 
at least five Summer Tanagers [...] immediate- 
Fif ure 1 . This Werm-eating Warbler, found and photographed 
4 April 2009 at Jeddore, Nova Scotia, was far beyond its breed- 
ing range and represents the Atlantic Provinces' earliest record 
ever — and among the first signs of the unusual April fallout. 
Photegmph by Lucas Berrigm. 
ly followed two southerly airflows” on 13 and 
20 April 1978 (Vickery 1978). Another fallout 
beginning 21 April 1991 in the Maritimes, 
New England, and farther west was attributed 
to a “big coastal storm that pushed migrants 
out over the Atlantic” (Kaufman 1991). In 
2001, Brinkley (2001) notes that “particularly 
in Nova Scotia, a fallout of cardinalids, chiefly 
Blue Grosbeaks, Indigo Buntings, and Rose- 
breasted Grosbeaks, occurred early and on the 
heels of a coastal northeaster (‘Carolina low’) 
that moved rapidly up the coast 18-19 April.” 
McLaren (1981) concluded that a high inci- 
dence of spring vagrants on Nova Scotia is- 
lands was related the mean southwesterly air- 
flow along the East Coast. 
Compared with past examples, the two 
April 2009 events were unusual in the early 
arrival, number, and variety of overshooting 
Neotropical species involved. Resources circu- 
lated via the Internet allowed us to look more 
closely than in the past at patterns and cir- 
cumstances associated with these fallouts. The 
species involved, and the 
northern limits of their normal 
breeding ranges along the At- 
lantic Coast, are presented in 
Table 1. 
Most of the species are 
known to be trans-Gulf of 
Mexico and/or trans-Carib- 
bean nocturnal migrants. In 
addition, a Swallow-tailed 
Kite and a Loggerhead Shrike 
were found 10 April in Nova 
Scotia, but these birds might 
not have been part of the 8 
April fallout. The kite winters 
in South America but is be- 
lieved to follow a circum-Gulf 
migration (Meyer 1995), and 
migratory northern popula- 
tions of the shrike winter from 
the southern United States to 
southern Mexico, and they are 
known to be early spring 
migrants. 
A search of mailing list- 
serves, including rare bird 
alerts, for Atlantic Canada and 
the eastern and southern United States indi- 
cated that there were similar arrivals of these 
Neotropical migrants along the coast from 
New Brunswick south to New York and that 
these had arrived in numbers during early 
April along the Gulf Coast and in Florida. At 
the same time, very few were reported along 
the Atlantic coast south of New York or in- 
land in the northern states. We therefore in- 
vestigated possible geographical origins of the 
Table 1. The typical northern limits, in the East, of breeding ranges of birds noted 
in the present paper (as mapped in Dunn and Alderfer 2008). 
Cemrasn l^ame 
Scientific name 
Nertbern breeding Limits 
Swallow-tailed Kite 
Elamidesforkatus 
South Carolina 
Eastern Kingbird 
Tyranm tyrannus 
Gaspe, Quebec 
Loggerhead Shrike 
Lanius ludovidanus 
Maryland 
White-eyed Vireo 
Vireo griseus 
Massachusetts 
Purple Martin 
Prognesubis 
Northern New Brunswick 
Gray Catbird 
Dumetella carolinertsis 
Gaspe, Quebec 
Yeiiow-throated Warbler 
Dendroica dominica 
New Jersey 
Prothonotary Warbler 
Protonotaria dtrea 
New York 
Worm-eating Warbler 
Helmitheros vermivorum 
Massachusetts 
Louisiana Waterthrush 
Seiurus motadlla 
Southern Maine 
Kentucky Warbler 
Oporornisformosus 
Connecticut 
Common Yellowthroat 
Geothlypis trkhas 
Southern Labrador 
Hooded Warbler 
Wilsonia dtrina 
Connecticut 
Summer Tanager 
Piranga ruber 
New Jersey 
Scarlet Tanager 
Piranga olimea 
Gaspe, Quebec 
Rose-breasted Grosbeak 
Pheucticus ludovidanus 
Gaspe, Quebec 
Blue Grosbeak 
Passerina caerulea 
New Jersey 
indigo Bunting 
Passerina cyanea 
Central New Brunswick 
VOLUME 63 (2009) 
NUMBER 3 
365 
