The creative study of birds through art, photography, and writing

Short-eared Owl Wing-clap Flight Display

by Bryce W. Robinson

Breeding flight displays in birds are a blend of the bizarre and the fantastic, a show of a birds talent and specialty in communicating it’s unique ability to portray fitness. The Short-eared Owl is no exception, as a low consistent hoot softly settles on the sky, while the bird flies with deep, moth-like wingbeats. Then, as if in suspense, the bird begins to clap its primaries in rapid motion, falling from the sky. After multiple claps and an appreciable loss of altitude the bird spreads its wings and continues its deep wing beats as before. The wing-clap is displayed in seeming desperation, as if the bird is throwing all caution to the wind to produce the most excellent round of claps for onlooking (or listening) females, and intruding males.

I rarely post videos back to back, but I’m making an exception this time because in the same evening I was privy to both Long-billed Curlew and Short-eared Owl flight displays. Both were “on my list” of behaviors to capture on video, and my excitement for capturing both in one evening is too difficult to quell. So I share…

This bird flew tirelessly. For near an hour, the owl flew in the sky performing wing clap after wing clap, all the while letting out a low consistent hooting barely audible to my ears. What a scene, and such a scene that I encourage anyone in the area of breeding Short-eared Owls to search out the chance to observe this behavior in real time. It’s bizarre, but it is at the top of the list for must see in behavior birding, and for good reason.

In the future I’ll be refining my camera skills and upgrading my lens, all in hopes of getting a more clear documentation of this behavior. For better video quality, click through the video link and watch on Vimeo in HD.

Long-billed Curlew Flight Display

by Bryce W. Robinson

The Long-billed Curlew has a bizarre courtship flight display, not unlike many other members of the family Scolopacidae. The male flies tirelessly in broad undulating circles, broadcasting a mournful whine into the sagebrush strewn hills. Having always been enamored by the spectacle, I made it a goal and was extremely pleased to capture the display on video.

If you haven’t heard of the Intermountain Bird Observatory’s Long-billed Curlew Project, I’d like to use the above video to make an introduction. Long-billed Curlews are facing threats in the west, on multiple levels. For many years now the impacts of landscape change have added stress to nesting curlews. Habitat loss from development, degradation from grazing, ATV recreation, etc. are all causing added stress to the birds ability to reproduce. On top of that, IBO has found that there is an issue with folks shooting curlews. What reasons there could be for shooting a curlew escape me, but it is an issue nonetheless and one that IBO attempts to overcome through education and outreach.

On top of these issues, these birds are facing threats off their breeding grounds as well. Contaminants on the wintering grounds add yet another stress to these birds. IBO has deployed satellite telemetry units on a handful of birds to fully understand their year round distribution and where particular populations may face threats.

Stephanie Coates, an all-star of bird biology, recently started her pursuit of a master’s degree in biology at Boise State University. She is working with IBO on their curlew project, and has started a website to chronicle her work and the work of the field crew. Follow along and check out live viewing of curlew movements via satellite imagery, great photos from the field crews, and more.


Recording Evening Grosbeak Calls in the South Hills

by Bryce W. Robinson

Female Evening Grosbeak - Coccothraustes vespertinus.

Female Evening Grosbeak – Coccothraustes vespertinus.

Last weekend I journeyed to the Sawtooth National Forest in Southern Idaho. I was focused on recording the “South Hills” subspecies of the Red Crossbill. Due to the absence of Red Squirrel in the South Hills, the Lodgepole Pine of that area are absent of a seed predator, save the Red Crossbill. As such, the Red Crossbill have a steady food supply throughout the year, causing them to be resident rather than the typical seasonal nomadism of other Red Crossbills. The relationship with the Lodgepole Pine has become an arms race of sorts, where tree and bird are adapting one after another to overcome the each others adaptive advantage. This in turn has shaped the morphology of the crossbills. They are now distinct in morphological characters such as bill shape, but they are also distinct in call type which is likely a result of their long isolation from other crossbill populations. Thus is the reason for my interest in obtaining an audio recording. For a more complete story about the “South Hills” Red Crossbill (Type 9), see Benkman et al. 2009.

This is all in depth (and perhaps unnecessary) background to why I ventured to the South Hills. Regardless, I spent hours searching all areas that I was able, but to no avail. I couldn’t find the crossbills. Some roads were not open due to remaining snow, so my ability to search was limited. Still, I was disappointed. The birding was good nonetheless. So much so, in fact, that I was able to find another project to augment the absence of the Crossbills.

I found a small flock of Evening Grosbeak, a nomadic mountain dwelling finch that one does not happen upon enough.  The grosbeaks were vocal, so I took the opportunity to record their calls. After all, I didn’t want to leave empty handed. I’m happy I did, because after some research I’ve discovered that the Evening Grosbeaks are like the Red Crossbill, as they too have a number of distinct call types that correspond to particular groups. At the moment there are 4 recognized types.

Male Evening Grosbeak - Coccothraustes vespertinus

Male Evening Grosbeak – Coccothraustes vespertinus

Here is the recording I took of the Evening Grosbeak vocalizations:

From the spectrograms of this series of calls, I was able to identify the call type for this group, which corresponds to geographical origin and even perhaps subspecies (Sewall et al. 2004). The call type for these birds is Type 1 as we would expect in this area. Type 1 is a group that inhabits the northwestern portion of the range of the Evening Grosbeak. Below I’ve presented the first spectrogram of an identifiable call note in black and white, followed by a colored spectrogram. I couldn’t decide which was more attractive. Forgive the formatting of the spectrograms as well, I’m just starting to get a hang of how to produce these images.


Figure 1. Two call notes given by an Evening Grosbeak. Time is shown on the x-axis in seconds, and frequency is shown on the y-axis in kHz. The call note on the left is the typical sweep call not unlike the flight call. This is the signature referred to as Type 1. The second call is a broad-band fluttered call. This particular bird was giving paired calls most often as illustrated, but at times calls were paired as two sweep calls (figure 2). Note the fundamental (darkest) with the first harmonic above each call.

Figure 1 shows a paired call, where the second call is quite different. The bird I was recording was repeating this sequence. I’ll need to research further to discover what the role of particular calls are, if it is even known. It is curious why these calls are paired, and why at times the bird would switch to a pair of the same call note (figure 2).


Figure 2. Paired call of Evening Grosbeak, both as sweep Type 1 calls. This paired call was less common than the pair seen in figure 2 for the individual calling.

I’ve been learning quite a bit about bioacoustics, the role of sound in nature, and how to properly analyze sounds using particular software. I decided to take on this objective to test my ability to go into the field, find my subject, get a proper recording, look at the sound using software, produce spectrograms, and communicate ideas. I “failed” at my objective of finding my target subject, but in doing so I stumbled upon something that taught me quite a bit. I’m happy about that, as it is a lesson in making an effort. Inevitably there is always something to gain.

Perhaps one of the most important discoveries that came from recording the grosbeaks was finding an eBird article discussing one Ph.D. students aspirations to catalogue the different types of calls, where the true boundaries are, and how much intermixing happens between individuals where type boundaries occur. The students name is Aaron N. K. Haiman at University of California, Davis. He has requested that anyone and everyone record call notes of Evening Grosbeaks and share with him. So, I’ll be sending him my recordings along with the information on location, time of day, etc. to give the recording context.

All in all, I’d say I had a Saturday well spent.

Referenced Information:

Benkman, C.W., J.W. Smith, P.C. Keenan, T.l. Parchman, and L. Santisteban. 2009. A new species of Red Crossbill (Fringillidae: Loxia) from Idaho. The Condor 111(1):169–176

Sewall, K., R. Kelsey, and T.P. Hahn. 2004. Discrete variants of Evening Grosbeak flight calls. The Condor 106:161–165

Singing Sagebrush Sparrow

by Bryce W. Robinson

I took this clip the other day in the Sagebrush strewn landscape of southwestern Idaho. I recorded the video by digiscoping using my ZEISS Diascope 65 T* FL. Normally, Sagebrush Sparrows are busy singers and will generally tolerate you in the area so long as you don’t pay them too much attention. But for whatever reason, no matter how far I was the sparrows on this morning were extra timid. On top of that, the wind wasn’t helping. Due to the wind and the distance from the bird, you can’t really hear the singing. To add one more difficulty to getting the song recorded, there was a lone bull nearby that was constantly growling. I didn’t know bulls growl… So, there is room for improvement for recording video of a singing Sagebrush Sparrow.

Anyway, I’m still pleased with the outcome. I do think I need an external, directional microphone for recording singing birds. Digiscoping really caters to sparrows and other passerines that are more flighty, but it doesn’t capture the song well. Still, It’s really nice to have quality glass to help with the effort. I’m really excited to apply the technique to some of Alaska’s more timid birds this summer, such as the singing Arctic Warbler and displaying Bluethroat.


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