Wet, muddy April. Cottontail disappears!

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

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!

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

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!

Mid-April Update

I’ve now been at Chicken Camp for a few weeks. Ryane and Gail got the camp set up and the crew oriented, so I was stepping into a well-oiled machine when my 9-seater turbo-prop touched down in Riverton. There was a light snowfall just after I arrived, and that lead to some great photo opportunities on Chugwater. I shared my first morning on the lek with a birder/blogger/education graduate student named Christian who was visiting camp for the day. It was fun to share the grouse and our project with him, and to learn about his ambitious project to use a “big year” (seeing as many species as possible) as a way to connect with birders and learn about how they use technology and form communities. His website is worth a look: thebirdingproject.com

 

Female sage-grouse solicits a displaying male

Female sage-grouse wanders to the edge of the lek

Territorial male sage-grouse evicts a non-territorial male from the lek

After Christian left, we caught a HUGE winter storm, that over two days dumped at least a couple of feet of snow. I can only remember one storm that left this much– back in 2007, we had another 2+ feet that fell just after peak breeding and left a 3 day hole in our daily observations at Monument lek.

 

Sunrise from camp

Needless to say we were kept off the leks for a few days for a few days with this year’s storm as well. Chugwater lek is fairly accessible, so we were back there after 3 days. Cottontail took another couple of days, and required a tough effort to forge a path there.

 

Photo courtesy Brett Sandercock

We had another visitor, Brett Sandercock from Kansas State University, who came out to Chicken Camp for the weekend. I knew Brett from my Berkeley days when he was a post-doc and I was a wee grad student. We’ve since crossed paths as grouse-ologists– Brett has been working on Prairie Chickens in the Midwest for a number of years. It was fun getting to show him sage-grouse for the first time!

 

 

We also managed a quick afternoon trip to the Nature Conservancy area in Red Canyon.

Lower reaches of Red Canyon

 

The snow seemed to extend the peak in breeding this year, and we had a lot of females showing up in the first week or so after the big storm. From the few banded females we have, we know they were there before the snow and came back again after, suggesting they might have abandoned their first nesting attempt.

 

Two banded males courting a banded female

A very few females we can tell individually even with out bands. Ryane had sent me a digiscope of a white-feathered female that was seen a couple of times early in the season. It came back last week, and one day I was on the lek and able to get some shots.

 

Leucistic sage-grouse hen with white plumage

Losing a nest is generally a bad thing, but our Game and Fish contact said that we shouldn’t be concern. Any females that got caught by the storm were breeding early, and have plenty of time to try a second nest. Add to that the huge benefit that the big pulse of moisture will provide to the ecosystem. It looks to be a green spring out here, which should mean lots of new growth and insects for the chicks.

 

With fewer and fewer females showing up every day, we finally have a chance to start our experiments for the year. I’ll leave the topic of those for another post.