Eat more cookies

My students and I met at Sanborn Lake Park in Stillwater yesterday morning to get a little bird banding practice in. We only had 4 nets up, and we didn’t have much luck. But we did catch two great birds – a Brown Thrasher and a bright, fall Warbling Vireo.

Brown Thrasher, photo by Vince Cavalieri

Warbling Vireo, photo by Vince Cavalieri. Note the aluminum band on the leg.

Warbling Vireo portrait by Jason Heinen

Warbling Vireos can be difficult to separate from the similar Philadelphia Vireo:

Photo by Bob Mulvihill, Powdermill Nature Reserve

Note the longer bill, paler throat, and paler lores on our Warbling Vireo. These, and a few other subtle visual cues, can help separate the species in the field. With the bird in hand, we were able to take measurements that confirmed our bird as Warbling based on significantly larger wing, tail, and bill lengths.

Migratory birds, even otherwise insectivorous birds, will gorge themselves on high carbohydrate foods in preparation for migration. The increased carb intake – and hormonal and physiological changes in the birds’ bodies – helps them to deposit fat that fuels their long journeys over inhospitable terrain. A bird’s preparedness to make a migratory journey can be assessed by quantifying the amount of visible fat on the body, which is usually apparent through their translucent skin. I scored the fat on this bird a “3″. Its furcular hollow was bulging with stored fat, and its belly was completely covered with a layer of fat.

Warbling Vireo, photo by Vince Cavalieri.

Warbling Vireo range map: