Encounternet Tags

Encounternet Tag Solar Power edition.

We are making some progress with the Encounternet tags. Getting the tags out on the birds has gone quite well actually. Ten or 11 of our 13 tags are deployed on male sage-grouse at the moment, and we kept those last two back to be able to carry out tests back at camp. Frank and Julia have excelled in the role of banding technicians. I’ve been out with them several times now, and many nights we’ll catch ~4 birds- a good haul and much better than our past attempts at spotlighting.

 

The harnesses seem to be holding up as well- none have fallen off yet, and the tagged birds are showing up on the lek and performing their full suite of fighting and display behaviors.

Male "Tiny Dancer" wears a tag on his rump. He continued to mate with females after his tag was put on.

As a reminder, our goal with these tags is to collect positional data on the males, and to know something about their behavior at these positions. In particular, we want to know where the males are foraging so we can visit these sites and determine the nutritional and chemical quality of the sagebrush they are eating.

We are learning that getting these data off of the tags is a non-trivial task. One issue has been the relatively weak signal strength from the tags themselves. Traditional radiotelemetry uses lower frequency pulses that transmit long distances. The higher-frequency data transmissions from our encounternet tags do not travel well when transmitted close to the ground, and unfortunately sage-grouse spend virtually all their lives within a few inches of the ground. We’ve had to put our receivers higher up and a little closer to the birds. The grouse don’t seem to care about the pvc poles that are popping up on the leks. , We included perch deterrents on our permanently placed receivers to ensure that raptors don’t start to use them.

We’ve also had to do some optimizing on settings and firmware to actually get usable data, and now are starting to get some nice positional data on at least a couple of our correctly configured tags. I’ve figured out how to get the data into Google Earth to display. Here you can see movements from “Steve”, a Chugwater grouse who was first captured as a young bird in 2010 and has been a reliable lek male for the past few years. The points are roughly every hour, and the tracks show him moving a little less than a kilometer from the lek each day. Each day he seems to use a different area.

GPS points from male "Steve". It is so exciting for us to learn more about what these males are doing off the lek.

Next up, in addition to getting the remaining tags properly configured, is to determine which points to visit for vegetation sampling. These decisions will be based on a combination of GPS accuracy and likely activity, hopefully eventually with the accelerometer behavior data as well.

Top Dude

"Rick" is the top guy at Cottontail Lek.

I mentioned in the mid-season update that we were seeing our top males grabbing a particularly high share of the matings, especially on Cottontail Lek. This male was given a name that rhymes with “Rick”, based initially on the aggressive manner in which he claimed the territory formerly held by Gyrfalcon victim “Roundasaurus Leks”. Once females started breeding, it quickly became clear that this male was operating on a whole different level from other males on the lek.

“Rick” was constantly in motion, and every action had a purpose. When amongst the females, he was always strutting. His only breaks from this were to push other males away from his territory. Many male-male agonistic interactions involve prolonged “face-offs”, or facing past events, in which males sidle up to one another, face in opposite directions, and counter-position in order to attempt to gain favorable positioning for an attack without becoming vulnerable to a counter-attack [note- this was the subject of our collaboration with Sergio Pellis that recently appeared in Behaviour]. Just a few minutes on the lek during the peak in breeding and it was obvious “Rick” is playing a different game. He rarely engaged in face-offs. Instead his m.o. was to run up to a neighbor, immediately pummel him with his wings, then run back to the cloud of females in his territory and pick up with his display. Repeat all morning long.

"Rick" and his groupies.

Looking at the female’s mating behavior, “Rick’s” frenetic behavior seemed to be paying off. An unofficial tally shows Rick already with more than 75 copulations, and with more than 90% of all copulations on the lek. He has some impressive single-day totals, including what is I think a record for us of 32 copulations, including a dizzying stretch where he often exceeded 2 copulations per minute.While these data are still pending our search for copulations from the video and whatever happens during the remainder of the season, “Rick” is clearly a big winner. A quick glance through our past data suggests that the top guy usually gets around half of the total copulations, maybe up to about 2/3. We’ve never seen anything like 90%. Our highest total is 77, so Rick’s final total after we add in copulations seen by students on the video and any additional matings from the season, will almost certainly top this record. I doubt he will break the all time record that I’ve seen of 169 that Hartzler found in a Montana population some years ago, but for our Hudson leks, “Rick” is clearly a dude to be reckoned with! I really hope we are able to catch and band him at some point so we can see if his success carries over to next year as well.

2014 Fembot Experiments

Fembot "Salt" approaches the target area as males get excited.

Knock on wood, our behavioral tests with the robotic female grouse are going very well this year. With the robots already built, we were able to start right away. We’ve gotten (I think) 10 experiments in already, with hope for another 6 or so in the next few weeks. This has been fun for me, since this is the first time I’ve gotten to do real robot driving. Thus far I’ve driven in three experiments- two at Chugwater Lek and one at Cottontail Lek. A couple of times Gail and I have done simultaneous experiments on different leks- a first for us and a big advance in our ability to collect enough data to answer our questions.

A good experiment requires both opportunity and response. Opportunity comes in the form of males sticking around long enough in the morning to make it worth sending the female out on the lek. As with our previous experiments, we need to have a lek free of live females so we know who the males are courting and so our robot doesn’t need to compete with real females for attention. Some years these female-free windows are hard to come by, and males leave within minutes of the last female departure. Males need to be responsive as well- not too exhausted to care about courting one last female trundling on to the lek. Thus far we’ve done very well on both accounts.

So what are we actually doing this year? Our goals this year is to look at persistence in courtship. How long will a male engage in courtship, and how does this depend on factors such as seasonality and the female’s interest level. We are repeatedly testing males with trials that contain both interested and disinterested behavior, and getting measures (hopefully) early, mid, and late in the breeding season. We think differences in males behavior within each trial, as well as changes in his effort across the season, will reveal a lot about how he allocates his energy and his success on the lek.

Getting to participate in these experiments by actually controlling the robot has been a little stressful but also incredibly rewarding. It can be nerve wracking to drive the robot out and try to make her movements as life-like as possible. Not only do you have to keep the female upright and not tip over, but you have to maintain life-like movements throughout the trial. Don’t move too fast! Keep her head moving periodically! Don’t drive backwards! Aside from this, getting to interact with a wild animal in this way is just an indescribable experience. One recent experiment at Cottontail illustrates this. One male “Circle Butt” approached a little closer than we wanted for our protocol. I backed off a bit, and he also backed off somewhat and returned to his core territory. I moved back towards the intended target area, and “Circle Butt” came back closer. I backed off again, and again he retreated. It was such a thrill to be able to be an active part of this interaction.

A couple of previous posts on our robot experiments here and here. When I get a chance and more bandwidth I’ll add some video, but here’s a clip from 2012.

Mid-Season Update (2014)

March has almost literally blown by out here in Windy Wyoming. It’s been a pretty good month so far, in spite of some cycles of mild snowfall and mud that have made our field work difficult at times.

The breeding season started in earnest with a Cottontail Lek copulation on March 19th. This was tied for our earliest one on record. My impression is that the peak in breeding is fairly spread out this year, with female attendance and numbers of copulations not necessarily following the quick increase and decrease that marks some years. Maybe bad weather early in the season tends to synchronize the females more as the earliest hens delay breeding, but the lack of severe early storms or deep snow cover has spread things out this year? Just speculation.

Although it’s early in the season (and these data are only field observations  and still pending new events collected from our video records), reproduction seems particularly skewed this year. The top guy on Cottontail seems especially strong. I’ll have a quick post about him soon. He’s now got our single-day record for copulations, and really dominates the lek in ways we’ve not seen in the past.

Jess digs a cable trench.

Study-wise, we’ve got pretty much everything going now. Microphone arrays have been deployed at our two leks (Cottontail and Chugwater), and we’ve collected two mornings of recordings on each lek. We’re getting used to the new cameras as well. There are good points and bad points (mostly good points I’d say). It’s really nice to be able to view the videos so quickly, and in our initial data collection from the tapes we realized you could even zoom in on certain areas of the screen! That is a pretty nice feature.

We did not put in a microphone array at Monument Lek, nor have we been monitoring it on a daily basis. Bird numbers there are about what they were last year, so we’re not going to invest as much in it since the males seem to have shifted their territories to places we can’t easily observe them. Sad to take a break from this lek- but hopefully it will rebound next year and we will be able to record behaviors and conduct experiment there again in the future.

Speaking of experiments, we actually got a complete set of early season fembot experiments in. More about this in a future post.

 

Frank watches while John tests the range of the receivers.

Our collaborator John Burt just left. John has been building the advanced telemetry tags we are deploying this year. We got a couple on last spring– these new ones have solar to help deal with the power needed to run both a GPS chip and an on-board accelerometer. We’ve got 13 tags in hand, and are looking forward to collecting data on where these males are getting their meals (and how that impacts their ability to put on a good show). We’ve already caught a dozen males, so hopefully it won’t take long to catch a few more and get all of these devices out on birds and collecting data.

Encounternet Tag Solar Power edition.

We also enjoyed having Yale student Sam visit the camp for a few days. Sam is interested in the relationship between female preferences and male aggression, and thinks the sage-grouse might be an interesting system to look at this issue.

 

Dissection

It’s pretty amazing how much of unfortunate male Roundasaurus Leks was left after the Gyrfalcon killed him. Jen and Marcella were quick to get back to the lek and grab the bird before the falcon or any other animal else had a chance to eat much of it. Below are a few shots of what they found [IF YOU MAY BE UNEASY ABOUT SEEING DISSECTED ANIMALS, BLOOD, OR BODY PARTS, DO NOT SCROLL DOWN.

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Jennifer and Brecken get started on a make-shift table. Gloves recommended for this type of work.

(Most of) the syrinx, the sound producing organ. The yellow is a muscle that only male sage-grouse have out of all game-birds (at least as far as we know).

The gizzard was absolutely packed with sagebrush leaves. Surprisingly no traces of other plants, even though the (relatively) mild wet winter has greened things up a bit already.

Without teeth, a lot of the mechanical breakdown of foods occurs in the gizzard. Sage-grouse don't seem to use stones to help crush their food like a lot of birds do, although the walls of the gizzard contain tough ridges that help to grind things up.

There were still a lot of intact leaves. Jen was able to show us how some leaves are partially snipped from the plant, while others are cut down ot the stem. We will be looking for both types of foraging traces on plants when we examine diet quality later this season.

A male's testis (left) and brain (right). I'll leave this here without comment.