Monday, January 23, 2012

Snow, Songbirds, and Raptors

This week, Bellingham and western Washington received a major snowstorm.  At our house elevation, 310 ft., we got more than a foot of snow in one night, followed by two nights of arctic air (10 F/-5 C), then a heavy, warmish rain that melted it all.  This turned out to be spectacular weather for bird watching.



Our garden was visited by all sorts of passerines, looking for insects and seed under the cedars, and for suet or birdseed that we set out.  There were four Varied Thrushes that hung around continuously.  I heard them before I saw them...that strangely pretty, one-note call, which has been described as being ethereal.  All the thrushes have songs that many describe as beautiful or at least interesting: the American Robin, the Hermit Thrush, and especially the ascending-spiral song of the Swainson's Thrush.

These Varied Thrushes had spent the warmer parts of the year up-slope in the Cascade Mountains.  It was the snow that had driven them down to our elevation.
               
                                                    Female & Male Varied Thrush in young Alders

Female Varied Thrush
(Her feathers were puffed, providing extra insulation.)

Female with Pale Supercilium (Eyebrow)


Male Varied Thrush
(Notice the darker throat band.)

Song Sparrows, Dark-Eyed Juncos (Oregon J. variety) and Spotted Towhees were all scratching around in the snow.  They are all types of sparrows and they were busily looking for insects and seeds.  The Spotted Towhees also tend to be driven down-slope by the cold weather.  The Song Sparrows are a classic 'edge' species that likes fragmented forests and hedgerows.  We have a hedgerow of Red Cedars in our garden. 

Dark-Eyed Junco

Song Sparrow

Spotted-Towhee



(These were watercolor sketches that I did two years ago.)

A hard rain washed away most of the snow and our Merlin Falcon Foundation team headed out to look for raptors in the Skagit Valley.  Here you see, from left to right, Sara Davis (a volunteer), David Drummond (biologist and chief researcher), and Nathan Kline (intern and environmental science major at WWU).

There was a great deal of Bald Eagle activity.  We saw two young eagles (2 year olds) pirate a kill from a group of ravens, only to be displaced by 18 adult eagles.  Incredibly, one of the youngsters got away with a piece of meat.  Another time, we saw an eagle catch a duck and drowned it in a drainage ditch.  Eleven other eagles quickly joined it and it found itself defending its prize.  Unfortunately, I only have one poor photo of this, because I was driving, it was raining, and we didn't want to influence their behavior by getting out of our vehicles.

The eagles were perched in Black Cottonwoods, tall broadleafs and conifers at the edge of farm fields.  When they observed raven activity or a successful hunt of another eagle, they would leave their perches and try to supplant the original bird.

Rough-Legged Hawks come south from the Arctic to spend the coldest months in our region.  They are often confused with Red-Tailed Hawks, but there are some physical and behavioral differences.  Like most field observations, there are always exceptions, but here are my thoughts.  Rough-Legged Hawks have feathered feet, unlike Red-Tails...good for cold weather.  Their underwings have dark patches at the carpals (wrists), whereas the Red-Tails have dark patches on the leading edge of the wing at the radius/ulna.  The Rough-Legs seem to have smaller heads, beaks, and feet.  They also seem to perch on lower, thinner branches than the Red-Tails.  Finally, and this is very subjective, Red-Tailed Hawks seem to me to be more robust in their flying, hunting, and diet.     
Rough-Legged Hawk

Rough-Legged Hawk (light color variant)

dark variant, Rough-Legged Hawk preening


A day of sloppy, cool weather turned out to be a good day for seeing raptors.