Map quiz 1 - answer

Map Quiz 1 - Answer

The map below is the full western hemisphere map for our quiz bird. Note the observations in Argentina. Since this is a year-round view of the species it could either be a widespread resident bird, or a long-distance migrant that breeds in North America and winters as far south as Argentina. Our quiz bird is heavily encountered in the western United States and the Canadian Prairie Provences. We can learn a bit more by looking at this species' range at its western edge. In California for example, it seems heavily represented in the Central Valley, yet not on the coast. It occurs widely in eastern Oregon and Washington but again seems largely absent from coastal areas. There also appears to be a scattering of vagrant records from the eastern seaboard, Great Lakes, and Florida. The higher frequency at the very southern tip of Florida suggests wintering. Looking further south we see a clear line of distribution through Central America south to Panama. In South America, however, our data are sparse, and more difficult to interpret. What we do see is that there are a few observations in Argentina, but not much to the north. Could these be vagrants? Unlikely, but a more plausible scenario is that this species reaches Argentina in winter.

Given the patterns observed on these maps we can make the following deductions. Our quiz bird is a widespread breeder in the Great Plains and then occurs in mainly agricultural and riparian areas west of the Rockies, being absent from the highest mountain regions. It appears to be a clear long-distance migrant, as evidenced by its occurrence on the Atlantic Coast, and its apparent southbound migration through Central America to Argentina. It possible winters in extreme south Florida.

There are only a few species that show this kind of pattern. Some of the high arctic breeding shorebirds like Baird's Sandpiper might be similar, but are more widespread in the East and along the Pacific Coast, and we see no evidence here of a high arctic breeding distribution. The few records for the Yukon and the Northwest Territory could be vagrants.

Our bird is one of the longest-distance migrant raptors on earth. The Swainson's Hawk undertakes an annual migration that carries it from breeding areas as far north as the Canadian prairies, across Mexico and then Panama en masse, to winter in the Pampas of Argentina. When we begin to collect more data from South America, we'll be able to connect the dots a bit better between Panama and Argentina, and begin to understand how these birds cross the high peaks of the Andes on their way south!

Thanks for eBirding,

Team eBird.