A studio for bird study

Tag: boise

November 16, 2016

A Green Heron GIF to illustrate Tail Flicking Behavior

by Bryce W. Robinson

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While photographing a vagrant juvenile Green Heron (Butorides virescens anthonyi) along the Boise River in early November, I noticed a behavior I wasn’t aware of for this species. When I would get a bit too close the heron would notice me, stop foraging, and flick it’s tail while it slowly walked away, as if it had a nervous tick.

Tail flicking is a behavior that many species exhibit. A recent study with the Black Phoebe found support for the explanation that tail flicking was a sign of vigilance to predators, a topic I’ve written about here. When the bird flicked its tail, the predator got the cue that the bird was aware of its presence and the predator had lost the advantage of surprise. This seemed to make sense in explaining the behavior of the Green Heron I stalked on the Boise River. Each time it began flicking its tail, I’d let off until it relaxed and continued to forage.

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April 27, 2016

Singing House Wren on the Boise River

by Bryce W. Robinson

 

I recorded a singing House Wren (Troglodytes aedon) today while banding birds along the Boise River with the Intermountain Bird Observatory (note the bird is banded!).

Although spring migration hasn’t hit in its entirety at this site, the House Wrens seem to have arrived in full. There are at least three different individual males singing in the area, and I’ve noticed an additional four individuals in the area as well. The House Wren population at this site seems to be healthy.

Unfortunately the video I recorded does not capture the song of the House Wren. I wasn’t too far from the wren, but I believe the inability of the phone to capture the song is related to the masking of other noises in the environment (and the iPhone’s lack of a directional mic). First and foremost it was a windy day, which I believe is the main contributor to the masking. On top of the wind was the noise of the busy highway, the noise of the Boise River, and nearby construction (all large bandwidth, but mostly low frequency). With both natural and anthropogenic noise, I wonder how House Wren territory distributions differ between an area like this and a relatively noiseless area such as a remote forest location away from a river.

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House Wren (Troglodytes aedon) banded at the Intermountain Bird Observatory’s Boise River site on the east end of Boise, Idaho.

Despite the heightened noise, the wrens in this area seem to be thick and continuing with life as they would. A study may enlighten us on the human noise impacts coupled with natural noise (rivers, etc.) on bird territory distributions like in this case, but if I were to hedge a bet I’d say the House Wren is one species that seems to weather the added impacts of humanity enough to maintain a regular and healthy population within human disturbance areas.

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January 30, 2016

Banded Golden-crowned Kinglet

by Bryce W. Robinson

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This past fall I helped the Intermountain Bird Observatory band birds on a number of occasions at a site along the Boise River. I’ve returned to the location on occasion throughout the winter to bird, and every time I find a small mixed flock with banded individuals throughout.

The other day I made attempts to photograph banded birds to capture band numbers and identify individuals. Easier said than done when the flocks are busy foraging. I came away with some good photos, but nothing that put together a full sequence or even the last few digits.

It can be said, however, that these birds are most likely the same birds that were banded here in October. The other most plausible explanation is that some were banded at IBO’s other site, only a few miles away on the top of Boise Peak. I’m unfamiliar with the literature on winter movements of the Golden-crowned Kinglet, so I don’t have an idea if holding a small range throughout winter is common for this species. Still, the birds I photograph seem to be staying put which surprises me in some way. Perhaps the inclination of the flock to stay within a small range speaks to the quality and perhaps importance of the habitat provided by this relatively wild portion of Boise’s section of the river.

Time to read, and think some more.

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Video | January 5, 2016

American x Eurasian Wigeon Hybrid

by Bryce W. Robinson

 

The phenotypic expression that results from hybridization is fascinating, especially in colorful birds such as the male ducks. One duck hybridization I enjoy is the American x Eurasian Wigeon. The subtle combination between the traits of the two species is pleasing to the eye, but also presents a fun and satisfying ID challenge.

I found a drake American x Eurasian Wigeon the other day in a large group of American Wigeon feeding on a grass field at a large sports park in Boise, ID. The winter group that frequents this field every year generally holds a drake Eurasian Wigeon. This year no Eurasian, but a hybrid.

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Note the retention of the American Wigeon head pattern. The Eurasian has a beautiful red-orange head with a golden fore-crown. The neck and auriculars do not differ in color than the superciliary and hind-neck as in the American. This hybrid holds the American pattern, but with strong Eurasian coloring throughout the head. The other most obvious quality on this bird is the gray flanks unlike the American Wigeon which have rufous flanks. Thus, the combination of American head pattern with reddish hints and the gray flanks are enough to confidently call this bird an American x Eurasian Hybrid.

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Eurasian Wigeon sure show up regularly each winter in N. America. I’d love to know if the regularity of Eurasian in N. America mirrors the regularity of American in Asia. It’s fun to wonder, but with the growing popularity of eBird, answering these types of questions are beginning to seem more and more possible.

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