A studio for bird study

Tag: behavior

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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October 1, 2016

Black-bellied Plover (Pluvialis squatarola) Feeding on a Jellyfish

by Bryce W. Robinson

 

For the past two weeks I stayed at a small cabin along the Bristol Bay coast of the Alaska Peninsula near the village of Egegik.  I was part of an expedition to trap staging Bar-tailed Godwits (Limosa lapponica) led by the shorebird aficionado Dan Ruthrauff of USGS, accompanied by Lucas DeCicco, Stuart Fety, and Jaime Welfelt. We had poor luck with godwits, but had a spectacular time with the avifauna that was present. I have a lot of content to share from the expedition, and will start by sharing a clip of a Black-bellied Plover (Pluvialis squatarola) feeding on a beached Hydromedusae (Jellyfish).

Although not mentioned in any literature on diet of the Black-bellied Plover (so far as I’ve found), there is discussion of the behavior for Rock Sandpiper (Calidris ptilocnemis; Gill et al. 2002). Apparently the birds feed on the gonads of washed up jellyfish. There were many jellyfish that were left on the tidal flats each day as the tide receded, providing an ample food source for staging plovers preparing for the next leg of their fall migration.

Referenced literature:

Gill, Robert E., Pavel S. Tomkovich and Brian J. McCaffery. (2002). Rock Sandpiper (Calidris ptilocnemis), The Birds of North America (P. G. Rodewald, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America: https://birdsna.org/Species-Account/bna/species/rocsan

DOI: 10.2173/bna.686

 

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August 17, 2016

Spurting and Filter Feeding Behaviors of a Juvenile Red-necked Stint (Calidris ruficollis)

by Bryce W. Robinson

 

Apart from its scarcity and place as a formidable ID challenge, juvenile Red-necked Stint (Calidris ruficollis) is an excellent late summer encounter in Alaska because of its focus on feeding and building fat stores for migration. This focus makes the stint a great subject for close proximity observation, photography, and video. Interactive birds that tolerate your respectful but close proximity are the most fun.

While taking advantage of one such bird, I noticed a somewhat atypical feeding behavior. I was able to capture the behavior in the clip above, as the bird sifts through the water, filter feeding in a way, and consumes small items when it happens upon them. I’ve seen this before in other peeps, but it is certainly an uncommon feeding behavior.

Spurting is an even more uncommon feeding behavior, but one that is regular in many shorebird species (Fellows 2013). Fellows (2013) offers the following description of the behavior: “the bird dips its bill into the water for a couple of seconds, or sometimes a bit longer, presumably to obtain food. It then withdraws its bill and slightly pushes its head forward, usually (though not always) with the bill lowered and then ejects or spurts a stream of water, as if ridding itself  of surplus liquid taken in while feeding underwater. The bill is then reinserted in the water and the sequence is repeated“.

I’d never seen anything spurt before until I watched this juvenile Red-necked Stint  filter feed in shallow water this summer. Unfortunately the video above doesn’t capture anything but filtering, but I was able to manage a decent photo of a spurting event.

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Photo 1. A spurting juvenile Red-necked Stint at Safety Sound, Alaska. Note the stream of water trailing from the birds bill.

I feel quite fortunate to bear witness to spurting behavior. Special thanks to my friend Luke for not only knowing the name of the behavior, but also letting me know of a note that names and details the behavior in shorebirds (Fellows 2013). Excellent behavior and excellent birding.

Referenced Literature:

Fellows, B. 2013. Spurting Behaviour in Wading Birds. Wader Study Group Bulletin 120(3) pp. 208-209

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August 8, 2015

Short-tailed Shearwater

by Bryce W. Robinson

I’ve seen a lot of North America’s birdlife, but there are certain bird groups where my exposure is lacking. One area is birds of the sea, or what we refer to as pelagic species. I haven’t seen many of these birds, particularly those that belong to the order Procellariiformes. In fact, I can count on one hand the number of species from this group that I’ve seen. So understandably I’d be interested in gaining more exposure in any way.

The other day I was birding the western Alaska coastline with my friends Neil Paprocki and Ellen Whittle. We were paying a lot of attention to the sea because we were looking to see puffins and a few loon species. I myself have spent a great deal of time watching the sea from the Alaskan coast, and I’ve never seen anything from the order Procellariiformes. On this day I had a first. We noticed a dark bird floating along the shoreline, maybe 100 m out. After scoping the bird, I knew that it was a Short-tailed Shearwater, a lifer for me and a long awaited bird. I was, to understate it entirely, excited.

The sight raised one thought in my mind, that the bird was obviously ill in some manner. It seemed to be sleepy, unconcerned by our presence, and very near shore (uncommon among these types of birds). So, something was likely wrong with the bird. Still, I took the proper satisfaction from studying the bird and enjoying its subdued behaviors.

I took some video (above) using my Zeiss Victory Diascope 65 F* TL that show the bird at a peak in its activity while we were watching. Notice the bird take a drink at the end of the video. If we drank seawater we’d in effect die of dehydration due to the high salt concentration. But, seabirds can drink saltwater. They excrete the excess salt through their nostrils. Observing this bird drinking the saltwater, and recalling their adaption for surviving life on the ocean was another moment where I saw something in real time that I had read about previously. Such an incredible experience, and behavior birding at its best.

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