Willow Flycatcher

Empidonax traillii

Formerly lumped with the Alder Flycatcher as the Traill’s Flycatcher, the AOU gave the Willow Flycatcher full species status in 1973. While the Alder Flycatcher breeds mostly in Canada, the Willow chooses more southern latitudes. The northern limit to their range is southwestern Canada. Except for the south-eastern USA, this bird will breed throughout most of the USA. Winter will find them in southern Mexico, Central America, and northwestern South America. They may live as long as eleven years.

In 2003, I was tasked with collecting a list of images for the San Diego County Bird Atlas by the San Diego Natural History Museum’s very own Phil Unitt. As the time for publishing approached, they had most of the subjects represented by images from veteran photographer Tony Mercieca. However, there were omissions. I volunteered to capture as many from the list as I could. The Willow Flycatcher was one species listed, and near the end of June, I delivered.

Taxonomists call for five subspecies of Willow Flycatcher:

• E. t. traillii breeds in southern Canada in Alberta, Saskatchewan, Ontario, and Quebec, as well as north-central and northeastern USA. They spend winters mainly from Panama to Ecuador.
• E. t. campestris breeds north to southern Canada from Ontario and Quebec to southern Alberta and Saskatchewan.
• E. t. adastus breeds in southern British Columbia, and in the USA to California east of Sierra Nevada range, and in the Great Basin and the Rocky Mountains. They spend winters mainly from western Mexico south to Costa Rica.
• E. t. brewsteri breeds west of the Cascades and in the Sierra Nevada Mountains from southwestern California north to southwestern British Columbia. They probably spend winters from western Mexico south to Panama.
• E. t. extimus breeds in the Southwestern USA, including southern California, Arizona, New Mexico (west of the Rio Grande), southwestern Utah, southern Nevada, and perhaps southwestern Colorado. Research suggests they spend winters in western Mexico south to Costa Rica.

Authorities listed the “Southwest Willow Flycatcher” (E. t. extimus) as endangered in 1995. Scientists believe habitat loss and cowbird parasitism are the root causes of their decline.