Tag Archives: sage-grouse

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).

Trait Variability review now available online early

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Some papers bloom quickly from concept to publication, while others resemble periodic cicadas, spending years growing in the shadows before finally emerging into the light of day many years later. An example of the former is the technical review that our collaborator Jen Forbey is leading. This paper is the outcome of our workshop at the International Grouse Symposium in Iceland last summer, and our revisions are nearing completion.

As an example of the latter, take the review on within-individual trait variability that is now available online early in Advances in the Study of Behavior. Gail first conceived of this paper as a postdoctoral scholar at Cornell, and the paper became a framework for some of our early grant proposals with the sage-grouse. At that point we turned our attention to empirical work with the grouse, and developing a more specific framework for interactions on the lek that became it’s own review. Now, with the help of Gail’s former graduate student (and before that, grouse intern), Conor Taff, we’ve finally finished!

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.

 

2016 Experiments

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Now that it is mid-April, most hens have mated and started their nests nests and we are past the peak in female attendance on the leks. This gives us the opportunity to study how the male sage-grouse react to stimuli we provide without competition or interference from real hens.  That means Experiment Time!

 

This year Ryane has designed a study to look at how the males use public information on the lek. We usually think of leks, particularly classical leks like the sage-grouse have, as being very open where everyone can see what everyone else is doing. This isn’t necessarily true of all leks, even sage-grouse leks. We tend to choose more open breeding grounds because it makes our job of tracking and IDing birds much easier, but some peripheral males display from the sage, and some entire leks lack a real central clearing.

Our goal is to understand more about how males take into account various cues that a female is around- whether it’s the sound of a female nearby or the sounds of other males courting a female. To isolate these, Ryane designed a barrier that obscures part of the lek from some males. Then we can provide a stimulus to one side (sound playback from our rock speakers or sending the fembot out of a blind), and watch how males on the other side of the barrier react.

Ryane and Andre setting up the barrier

Note that the birds can (and do) go around, over, and even through gaps in the barrier, so that this isn’t constraining their movements in any way, and the barriers are typically up for only a day or two at a time.

What can we learn from this? It will help us learn more about the importance of social responsiveness in animal courtship and mating. Much of our work over the past years has been to demonstrate that it’s not just how hard males work for the female, but that males also differ in how sensitive they are to changes in the social environment, and this can also relate to differences in their success with females. It will also tell us more about the importance of the sensory environment- the topic of our next grant proposal!