iSeeChange: Birds Not Thrown Off By Warm Temps

May 10, 2015

Spring is in full effect, and for quite a while birds have been migrating through the area.  One listener, Marylin Stone, commented on the iSeeChange website that she noticed, for the first time this year a Bullock's oriole and a hummingbird, she wasn’t positive which species.  I brought this observation to Jeff Birek, a biologist with the Rocky Mountain Bird Observatory.

Black Chinned Hummingbird
Credit Flickr User colorob

“It’s probably a Black Chinned Hummingbird,” says Birek, “they do like to migrate through this area.  However we also have a breeding hummingbird that spends it time throughout the summer here.  That’s called a Broad Tailed Hummingbird. Bullock’s Oriole both migrate through here and breed in the state of Colorado.  They tend to like riparian areas, that is, areas along rivers.”

He says that this is a pretty normal time to see them around here.  The warm spring may have thrown off the fruit trees in the area, but birds aren’t as easily confused. 

“Generally, the big thing that triggers birds is the change in day length that naturally happens throughout the northern hemisphere,” he says.  “As birds start to detect that they’re having these longer day lengths, they have a hormonal change in their body that cause them to start exhibiting migratory behavior and eventually leave for their breeding ground.”

Birek says that Colorado is currently in a big migratory wave, as more larks and sparrows make their way through the state.  Colorado, he says, is fortunate in that it’s visited by birds from the east and the west. 

If you’ve noticed signs of spring, or signs of summer, let us know, at