Tag Archives: lek

Trailcams are blowing my mind!

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Sunset, another time when the grouse may be courting!

I LOVE that I can still be surprised by the sage-grouse even after 10 years out here. Sometimes it is just a matter of luck, as in having a particularly wet spring and seeing Cottontail lek disappear under the rising waters of the reservoir at the far end of the valley.

Sometimes the surprise comes from a change in our perspective– in the tools we use to observe the birds and the questions we are asking. For example, we just watch birds on the lek in the morning. We know the birds typically arrive just as the eastern sky is starting to brighten, and hang out on the lek for some length of time depending on weather, number of females, etc. Then they go foraging. Our assumption was that very occasionally the birds come in at dusk, and we know that typically around the full moon males will congregate on the lek at night and potentially be displaying for much of the night (they often leave earlier in the morning at that time as if they’ve been working hard under the light of the moon). That pretty much sums up our somewhat naive understanding of the timing of sage-grouse lekking activity.

Trailcams allow monitoring around the clock in all kinds of weather

Thanks to five trailcams on loan from Tim Vosburgh, a biologist with the BLM office in Lander, we are now getting a much more systematic view of when males are present on the lek. We will need some time to go through all the thousands of photos we are getting, but we’ve found a few surprising things already:

Two males at Monument Lek already in a territorial dispute at 6PM

1)   Evening lek attendance can begin a lot earlier than we thought. We thought based on a couple of encounters with birds at dusk that males would not come in until well after the sun went down. Not so! We’ve had some really cloudy afternoons and have had males on before 6PM.

Almost all leks had displaying males after 8PM

2)   Evening lek attendance is very common. I just looked through a sample from about a week of activity from three leks, and I think males were present in the PM pretty much every day on each lek.

3)   (Pending more data) Evening lek activity seems pretty synchronized across leks. My suspicion before was that it might be driven by random attendance of a few males that would then spur more males to join. I was expecting to find patterns where one lek would be active and another would be empty. Based on my quick scan through the photos, I think males on leks may be pretty consistent in how they respond to environmental cues such as precipitation, wind, and cloud cover.

This is a very limited sample of leks right now, and mostly around the full moon. Hopefully next year we can start monitoring more leks and start at the beginning of the season.

And for fun, a couple of other lek visitors:

Wet, muddy April. Cottontail disappears!

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Ryane dressed for mud

As long-time readers will know, weather is often one of the biggest challenges we face when conducting field studies of the sage-grouse. While a warm, sunny April is more pleasant for us to be watching the birds, it can be tough on the grouse and they tend to get tired and not as responsive. Moderate precip is good for the birds (especially survival and growth of the chicks), but our fembots can’t drive well in the mud and sometimes it limits our ability to even get out to the leks.

 

This April has been schizophrenic, bouncing between 70’s and snow practically every week. It can go from green

to white again in just a day or two.

This week we moved well past “moderate” on the precip scale. A few days with significant rain events, followed by 2 days of snow, have left Government Draw a green mucky mess. Nowhere was this more apparent than Cottontail lek. Set aside that the two-track in was practically a stream. Kira and Jessica showed us photos and videos depicting a lek half-under water. The land on the far left of the observation grid had been claimed by rising water levels. Ryane and I went down in the afternoon to set up a playback experiment for the next day under the assumption that the lake level would have receded somewhat by then. Oh no. Like the old Johnny Cash song, “three feet high and rising”. Some stakes at the front edge of the grid were completely under water, and it looked like dry land extended only a few meters from the sage!

 

There's a lek under there somewhere!

We had been warned about the possibility the entire lower lek might flood, and maybe Gail had even seen this in the 2000’s before Cottontail became a focal lek, but this far exceeds any water level we had seen since 2012.

It is fascinating to see Cottontail this way. Cottontail has a secondary lek center up on a hillside. It appears that extreme weather events push birds up there, and in drier weather with enough grouse they colonize the flat area we consider the “main lek”. These cycles of changing population numbers and disappearing territory must keep both lek areas active.

To add to the surprise, there were 30+ males fully fighting and displaying at a little after 6PM! (it was a gloomy afternoon, and there were hens on in the morning).

Eagle!

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Golden Eagles are one of the main predators of grouse on the lek. Although we’ve only seen a handful of successful attacks, a fairly large proportion of “flushes” (i.e. rapid departures of most or all of the males on the lek) seem to be due to an eagle passing by or attacking the lek. We’ve had a string of such events on Chugwater recently. Very exciting for us, although frustrating when we aren’t able to do an experiment because the birds have all left!

Andrea Aspbury and colleagues studied lek placement and hypothesized that leks form in spots where grouse will be more able to detect approaching eagles. In their analysis, they found the placement of these traditional display grounds balance the need to force eagles to approach from the air (where they are more visible) and the need to make displaying males as conspicuous as possible to prospecting females.

 

Banded birds return! 2015 Field Season

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In spite of the painful adjustment to getting up hours before sunrise, the past few days have been a fun introduction to the world of the lek. At this point in the season, one of our highest priorities is to get photographs of the males’ tails during display- we use these to help identify each male based on the spot pattern (we call them “buttprints”). We recognize these patterns from our distant overlook hills with a good spotting scope*, and it is possible to get pictures of these with a point and shoot camera or cell phone using the scope. However, we typically take the photos from much closer. It is easiest to do this from the edge of the lek, which means relatively close encounters with the birds. Even our technician who has worked with sage-grouse before hasn’t gotten to see the lek behavior up close, so watching the struts and fights, hearing the grunts, pops whistles, and swishes, is a real treat.

Male helpfully displaying his bands from atop an anthill

Sage-grouse, like most birds, molt their feathers at least once per year. What this means for us is that the buttprint patters we use are only valid for one season, and the next year when the male shows up on the lek, he will have an entirely new pattern. Fortunately, our increased attention to catching and banding the males means we are starting to be able to follow males across years as well. For example, we caught one male “Steve”** in his first year on Chugwater, watched him establish his territory and return for several years, all apparently without mating with a female. This year we’ve had a good number of returnees already from last year’s captures, including males on both Chugwater and Cottontail that yielded a lot of behavioral data last year.

Encounternet male leaving lek

Encounternet male leaving lek- note the antenna extending from his lower back.

While we have had good success finding banded males, our resighting of birds with radiotags seemed less encouraging at first. Several encounternet birds returned but did not seem to have tags, and we were worried that our Teflon harnesses might be prone to falling off sometime during the off season. Eventually we got close up photos during the process of taking pictures for buttprints, and started seeing the antennas sticking out. The good news is the harnesses are still on, and that the males survived and are behaving completely normally. If there’s a cause for concern, it is that after molt, the feathers on the back are going to impair the solar charging of the tag. New tags we put out this spring will work fine this spring, but maybe not as well for subsequent years on the bird unless we can capture the bird again and tuck some feathers under the harness.

Along with identifying the birds, we are moving forward with data collection. If buttprints are Step 1, then getting the grid of survey stakes is Step 2. As the weather warmed and the snow melted, it was easier to get to Chugwater Lek, so that was our first target. The key is not only to get the uniform 10m spacing of stakes, but also to make sure the stakes are arranged in a way that makes hill observation and data collection from the video as easy as possible. Once we get the first square as square as possible, then it is easy to build out from that by sighting along the rows of stakes, checking 10m spacings as we go. Chugwater always seems to be really muddy when we lay out the stakes. The road to Cottontail was pretty bad, and we didn’t make it down until yesterday. Cottontail Lek is much bigger, and we ended up with probably ~100 stakes in the grid there!

Cottontail, now with grid!

Finally, the crew is starting to get used to the spatial mapping of the birds. We all went up to the Chugwater overlook once the grid was up to practice. Our “base” data collection is therefore in place- pretty happy to have that done relatively early in the season. Next up will be setting up the microphone arrays, capturing some birds and getting the position and movement data from encounternet, and hopefully some early-season robot experiments to form the basis for understanding seasonal changes in effort.

Chugwater hill blind at dawn, waiting for the stakes and birds to become visible.

Chugwater Lek view from the overlook hill

* We have had very good luck with Alpen brand scopes. Very nice quality for the price.

** In the field, we name birds based on their tail feather patterns, or other silly names. This seems to make learning the birds much easier on the field technicians. When our undergraduates collect behavior data back in the lab, we only refer to them by their number, so there’s no chance of biasing our data collection based on the name the male was given. Also, we have not seen Steve yet this year.