Rock ledge with a more thank 65-foot drop to the ground.

22 July: At least one of our nests has a young eagle yet to fledge! This bird is at least 62 days old and reluctant to leave the safety of the nest. This nest is more than 65 feet from the nearest safe ground, so this youngster may be wise to hang on for a while.

Four eagles fledged last week from three different nests. We caught up with one of the fledglings perched on a large rock outcrop about 100 meters away from its nest. We watched it for about 30 minutes before it took flight!  It flew with strong wingbeats for about 250 meters, then began gliding and landed a bit awkwardly on a sagebrush-covered hillside across the canyon. The bright, white band on the tail and stark, white wing patches were clearly visible to us. Summer is in full swing now, with temperatures in the low-mid 90s most days.

Golden Eagle Posse member Anne Hay filed this report and photograph shortly after the eagle she had been monitoring left the nest:

Fledging flapping its wings on a rock ledge near the nest.

“I was unable to visit the nest until Wednesday morning, and sure enough, the chick had abandoned the nest. The only bird I saw in the nest was a swallow, picking through the nesting material. I began searching, and 23 minutes later I spotted the fledgling standing near the ground on a small rock, west of the nesting area. About an hour after I arrived, the fledgling began calling out loudly. In the past, this usually meant an adult was visible, and sure enough, a parent arrived, dropping a small rabbit for the fledgling to dine on. The fledgling immediately ran to the prey and began mantling it, combined with peeping. The parent only stayed for 3-minutes. The fledgling fed for around 32 minutes, then walked a short distance west, and flopped down flat on the ground with its wings outstretched on either side. YIKES! Am I glad this wasn’t my first sighting of the fledgling! It looked like a dead eaglet! It only laid this way for 6-minutes, then it flapped/jumped onto a low rock in a shady area. It spent some time jumping between rocks in the sun, and rocks in the shade, preening, or looking around. At one point a female grackle began to harass the fledgling. This bird flew around the fledgling, from near-by rock to near-by rock, in two separate sessions, continually calling out. The grackle stayed for 19 minutes the first time, and 18-minutes the second time. Sometimes the fledgling watched it, sometimes it ignored it. Once the grackle flew at the fledgling, and pecked its tail.

Mid-afternoon an adult glides past, traveling north, over the rock formation and out of sight. The fledgling spies it, and begins calling. About 5-minutes later the fledgling begins moving west, first slowly, then faster, then it begins climbing the hill, hopping from rock to rock with some wing flaps until it is at the top of the ridge! From here the fledgling did a lot of looking around, preening, a little wing exercising, as well as a few very short flights along the ridge line. Twice the eaglet walked over the ridge top to the north, and out of my sight, then a short time after again reappeared on the top of the ridge line. I kept waiting for the flight off of the ridge, hoping it wouldn’t be a landing on the highway, but by 4:30, the fledgling still hadn’t taken the big leap. What a fascinating day!

Intern Pat Rodgers collecting prey remains from under one nest.

I’ve just begun to summarize our data from this year and compare with the previous two years. I’ll save details for our peer-reviewed papers, but this year has been quite a departure from 2009 and 2010 in several respects. The number of active nests this year was only about half of the number we’ve seen in each of the last two years, and far fewer of the active nests contained more than one chick. Our nighttime surveys indicate that both jackrabbit and cottontail populations have dropped markedly this year. We will be analyzing all of these findings for the next several weeks, but this study is becoming more and more interesting and stimulating some new questions about the cause of rabbit population fluctuations and the effects of these fluctuations on eagles and other predators. We’re seeing both a drop in the number of breeding eagles and an increase in the number of prey species showing up in the diet. We’re especially interested in finding out how habitat and human activities influence these results and how things will change next year.

I’m also anxious to compare our findings in the Bighorn Basin with a sister study site in Yellowstone’s Northern Range. This is the first year that Golden Eagle nests have been systematically surveyed there, and our colleagues in the Park have found more than twice the number of nest areas than expected!

Rugged terrain in the Big Horn Basin.

July 8: Summer has definitely arrived in the Bighorn Basin! Still a good deal of green and some wildflowers in bloom, but things are heating up and drying out. It was 93 degrees F. yesterday afternoon when several of us visited one of our successful eagle nests. The single fledgling left the nest more than two weeks ago, at about 54 days of age. She wasn’t quite ready for sustained flight yet, so she stayed in the rocks and sagebrush around the nest for several days before she finally took flight and left the immediate area. In the meantime, both parents continued to bring her freshly-caught prey. Our team began collecting prey remains in and around the nest to determine this family’s nesting food habits in 2011. Next week, I’ll post some photographs of this trip and what we discovered. Nearly all of the nestling eagles in our study area are nearing fledging. We have fewer active nests this year compared with the last two years, and most of our nests have only one chick. However, Bud and Dale Schrickling and Richard Brady and Sharyl McDowell have been monitoring one photogenic nest with 2 chicks. These two successfully left the nest several days ago.  Here are reports from the Shricklings filed June 23 and July 06 along with one of Dale’s fine photographs:

Meal delivery to the nest

June 23: “We had probably the most exciting three hours of this year, if not the total three years we have been monitoring nests. Normally during an observation year you are lucky to observe a single prey delivery. This day we witnessed a total of three deliveries within a three hour period. To make it even more fantastic, Dale got pictures of all three. In addition, Richard Chapman showed up a little while later and did the video interview, which was quite fun to do. He really seems to enjoy doing what he does and seems quite professional at performing it. Our No. 1 chick will be fledging within the next ten days. (our estimate). No. 2 seems to be at least a week if not more behind no. 1.”

July 6: “On 27 June we observed a lot of activity from no. 1 that would indicate she was getting ready to fledge. She would hop about the nest flapping her wings and actually rising above the nest a foot or so. No. 2 would just watch. We estimate that no. 1 is approximately53 -54 days old, where no. 2 is as much as a week younger. On 04 July we returned after a week of absence to find both chicks gone from the nest. On 05 July we went by the nest for a quick check and to see if there were any of the former chicks in the area. We saw one mature eagle do a nest fly-by, but that was all.”

Golden eagle

I was able to visit the nest area yesterday, and observed both new fledglings making good use of shade under a rock outcrop about 100 meters from the nest and one adult watching from the ground nearby – both fledglings looked healthy. Stay tuned for an update next week!

“We arrived at the nest on a beautiful and calm morning to find the chick up and about with one of the adults in the nest. The chick still had a mostly white head and chest with wings and back that were an uneven mix of white down and dark feathers (with mostly white down), and a bright yellow cere; we estimated the chick to be 30-35 days old. On this day of observation we learned a very important lesson in pronghorn parenting: never try to conceal your fawn in sagebrush 300 yards from an active golden eagle nest. At 10:15 we observed one of the adult eagles leave the chick in the nest and make a landing 300 yards in front of our vehicle. The landing was not a typical, smooth landing of a golden eagle; rather it was rough with wings spread wide for balance followed shortly by the use of the beak to tear and pull on the prey upon which it had landed. Then, from the nearby draw came at full speed three pronghorn antelope which chased the eagle off of its kill. The eagle came and landed 50 yards from our vehicle atop a telephone pole where it sat a few minutes before slicing and flying off for another attempt to enjoy its recently killed meal. We observed the whole ordeal play out as the two eagles would come to the kill and feed, and the pronghorn would return (an estimated 5 – 8 times) with relentless persistence to try and chase them away. We were both in awe at the fact that this could be a pronghorn kill and waited patiently for a view of the prey, when after about four hours one of the adult eagles drug a bloody and partially eaten pronghorn fawn on top of a large sagebrush. Both eagles fed on the fawn, but we watched one eagle feed till its crop bulged to a softball size projection on its chest, and guard the dead fawn for a little over two hours before we reluctantly left the spectacle before us. It was amazing and inspiring to see the persistence of the pronghorn and the power of the golden eagle, and it was a special reminder of the importance of this keystone species in the invaluable sagebrush steppe of Wyoming.”

It’s a fact of nature that some individuals die so that other individuals live. In this case, the parent eagles in Nest 7 took the life of a newborn pronghorn fawn to support their own family. We’ll be completing our mid-season rabbit surveys this week and should have a better sense about whether the main eagle prey in our study area has remained stable or declined since last year.

10 June:  Headed out into Bighorn Basin to check on a few eagle nests and follow up a lead on a Burrowing Owl nest I’d heard about.  Finally a good day for fieldwork, with temperatures in the 60s F, and relatively calm winds.  High clouds, but mostly sunny today.  I’ve never seen the Bighorn Basin so green this time of year . . .or any time of year, for that matter.  Daisies, Indian Paintbrush, and Scarlet Globemallow beginning to bloom, but no sign of Larkspur yet.  My first stop was along the two-track where the Burrowing Owl was reported.  Roads still a bit muddy!  Wow, it was worth coming out here, though.  I spotted the owl near her burrow – no other owls around, and no prairie dogs visible.  This was an active prairie dog colony two years ago, but apparently inactive now – I wonder if sylvatic plague hit this colony?  Several pronghorn around. One doe approached me, and I suspect that she had a newly born fawn nearby.  I backed away after snapping a couple of quick photos with my 500 mm lens.

I was able to visit four Golden Eagle nest sites and confirm that three of them are inactive this year.  The fourth nest has a nestling that is about 40-45 days old!  Overall, it appears that only about 16 of our nest areas are active this year, compared with 30 each in 2009 and 2010.  We’re exploring the possibility that cottontail populations have declined this year.  It will be interesting to see if the eagles that are nesting this year are including more species in their diet, instead of the >90% cottontails we’ve seen the last couple of years. Our Golden Eagle Posse members are monitoring several active nests.  The West Zone Team of Rosemarie Hughes, Anne Hay, Richard Gruber, John Ross, and Don Chaffey filed this report along with a beautiful photograph from nest 43 taken by Anne Hay last week:

“It was a little quieter this week than last.  One constant though was the nestling is sure talkative.  It was very boisterous the first day we were out and little more subdued the second day, even though when an adult was close by it would let us know.  The eaglet is getting darker every time we see it.  It is losing its fluffy white down and you can see it in the nest, especially when the wind is blowing, which it did Thursday, 2 June.  We estimate age at 30-35 days by seeing more feathers emerging from its sheaths.  The cere and feet are getting lemony in color as well.  We still see the little fluffy head peer from around the pine boughs that are still being brought into the nest.  We haven’t seen the adult bring any prey to the nest.  It comes in, checks on things, then leaves, spending less than 1 minute at the nest.  It was so windy on the 2nd of June it was hard to keep the scopes still.  There was a lot of ‘floating’ on the thermals activity too.  A couple of times an adult would ‘float’ right by the nest, then land.  One adult landed in the nest, followed immediately by the other, who arrived with vocalization, causing the other to flee.  The 2^nd adult appeared to be larger, so it appears it was the female, who caused the male to leave.  The chick appears to be quite hungry.  The crop is very flat.  We did see them soaring around the nest, checking it out, a few times today.  No pine bough or prey was delivered to the nest though.  There was no self-feeding either visit this week and we didn’t see the chick being fed.  Compared to last week, this was a very quiet week, except for the chirping nestling.”

I’m looking forward to getting back out into the field next week and receiving weekly reports from our Posse teams. I hope the roads dry out a bit–we expect our first eaglets to leave the nest in the next 7 – 10 days.

Dr. Charles R. Preston, Senior and Founding Curator at the Draper Museum of Natural History, Buffalo Bill Historical Center in Cody, Wyoming

19 July – There are still several eagle youngsters in the nest or hanging around the nest for shelter and continued feeding.  Richard Jones and I visited several nests last week and found that some young eagles that had fledged several days ago were back on the nest ledge, under rocky outcrops for shade.  Temperatures soared to 100 degrees F in the Bighorn Basin, so shade was popular and critical especially to youngsters who may have trouble with thermoregulation!

Research Assistant Richard Jones scans for eagle actiavity

We continued collecting prey remains from some of the nests that have been abandoned.  Most nests are filled with cottontails, cottontails, and more cottontails, but other nests held some surprises.  One nest near Meeteetse held the remains, including skull, of a pronghorn fawn, along with a jackrabbit pelvis, a red fox skull, at least two snakes, and a cast pellet full of raven feathers.  Another nest held the remains of at least two young coyotes!  We found a massive infestation of lice and other ectoparasites in one nest.  This particular nest was abandoned by its two youngsters about 2 weeks before they could fly – these pests may explain the early departure, and may provide clues to some of the nest failures.  They found shaded shelter beneath the nest site and were fed by parents for at least 13 days before they disappeared from the site.  At last observation, both birds appeared ready to fly.  These birds were banded, so we may be able to determine the fate of them one day.

Golden Eagle Posse members Dave Beckett and Barb Grant prepare for one of our nighttime roadside rabbit surveys

Nearly all wildflowers are past blooming in the Bighorn Basin just as peak blooming hits the Yellowstone Plateau and the high country.  I’ll be hitting subalpine and alpine sites this week with BBHC photographer Chris Gimmeson to capture new photographs for an upcoming book on the Draper Museum and for our exhibits.  Richard Jones and I will also be out in the Basin to continue documenting nest sites and collecting prey remains – we’re hoping for some cooler weather, and will keep you posted.

Golden Eagle Posse members Rosemarie Hughes, John Ross (back seat near camera) and Richard Jones (back seat away from camera) keep track of eagles in nest 23A

Here are some of the reports I received this past week from our two teams of our Golden Eagle Posse nest monitors from the same nest:

Report from Barb and Jeff Russell on 16 July:  We went to the nest about 6pm this evening – where it was 100 degrees – the first hour we thought we were watching both nestlings laying in the sun in the “spare room” (the small area to the left of the nest). After about an hour, we saw three eagles flying. One was the juvenile we’ve been seeing at the other end of the dirt road. At the same time that one of the adults briefly grappled with the juvenile, the other adult flew into the nest, touched down and flew out again – the chick jumped over and made contact with the adult. That’s when we realized – ONLY ONE NESTLING. We’re pretty certain it’s the smaller of the two, the head and neck are still pretty scrawny.  Not long after this contact one of the adults brought a rabbit to the nest. Then at 20:30 when we were getting ready to leave, one of the adults perched just a few feet directly above the nest for a minute or two. The nestling chirped and chirped. Then the adult repeated the first behavior – dropped briefly into the nest, the nestlings made contact and then the adult flew out and perched on the highest peak. We’ve not seen this behavior in previous visits; looks like adult may be encouraging nestling to fly? All in all an excitingevening!

Report on the same nest from Susan Ahalt and Nicole Suuck on 18 July:   Have been visiting our nest more frequently now, hoping to witness our chicks’ first flights.  One bird (we call Slug) is still in the nest.   The other baby that left the nest a few days ago apparently decided leaving home so early wasn’t a good idea so has been making his way back to the nest (we call this one Rock).  He spent most of the three hours we watched them calling for his parents and didn’t move from his rock.   The adults were gone a lot but ended up below the ridge point just chilling.   As it went from 66 to 85 in that same three hours it was a good idea.   

Richard Jones watches an afternoon storm approaching nest 25A. It's a tough job, but somebody's gotta do it!

Many thanks again to all of our Posse members.  I can’t include all of your reports each week, but I do read them all and look forward to following your progress.  Just a reminder, your data sheets and field journals are due when your adopted eaglets fledge.  That will be soon for some of you!  Stay tuned for further updates next week.  Best wishes, C. R. Preston

12 July – Vegetation in the Bighorn Basin is beginning to turn brown and crunchy, now, and most wildflowers have passed peak bloom.  You can really pick out patches of cheatgrass in some areas.  This alien, invasive species thrives in disturbed ground and can create real problems for wildlife and livestock grazing if it takes over too much landscape.  It dries early in the season and invites the spread of wildfire.  After wildfire, it often outcompetes native grasses and forbs, and thus takes over even more ground.  Bureau of Land Management, Park County Conservation, and several conservation groups are working to reduce cheatgrass in the Basin, but it is a tough job because of so much disturbed land around human activity.

I was able to visit many of our active and recently abandoned nests late last week and through the weekend.  In several cases, eagles that have successfully fledged continue to stick around the nest area.  Parents will continue to provision these youngsters for at least a few weeks longer.  Richard Jones and I captured and banded one of these birds on Friday; a big, healthy fledgling from nest 31A.  There are still a few nests containing eagles not quite ready to leave the nest on their own, but I’m anticipating that all successful nests will have fledged by this time next week.  We’re still going through data and observations from last week’s aerial survey to tablulate final eagle nest occupancy, success, and productivity for this year.  Stay tuned for our summary in the next few weeks.

This young eagle successfully fledged only a few days ago. Photo by C. Preston

Here are some of the reports I received this past week from our Golden Eagle Posse nest monitors:

Report from Anne Hay, Richard Gruber, and Don Chaffey on 08 July:  Well it looks like our #1-oldest chick has fledged, at least it looked about ready last week, and it wasn’t present this week.  We were unable, however, to see any signs of chick #1 in the area of the nest.  The remaining nestling is healthy, dark, and looks ready to go any day now.  It is certainly well fed!  There was already prey in the nest when we arrived at 0600, which our remaining nestling was picking on when we arrived, then ignored for much of the day.  At 0812 an adult arrived and the chick immediately pounced at the parent.  As the adult moved aside I could see the chick mantling the prey. 

Posse members Richard Gruber (left) and Don Chaffey relax while monitoring their adopted nest from a distant observation post... more than 700 meters distant! This nest successfully fledged two eagles last week. Photo by A. Hay.

The parent immediately left, at which time the chick closed its wings, picked up the prey, carrying it to the south side of the nest.  It did not feed on the prey, but after depositing it in the corner of the nest, walked back to the north side of the nest where it stood looking around.  At 1108 the chick moved to the center of the nest and fed on the prey that had been present when we arrived.  After a short feeding, the nestling then moved to the prey we had seen carried in, and began feeding on that.  We believe it was a young cottontail, as it had a white fluffy tail, although it was thin and quite small in size.

Report from Rosemary Hughes and John Ross on 11 July:   I was out the 6th, 7th, 8th and the 10th, Days 15, 16, 17 and 18, observing these beautiful chicks.  Can’t seem to get enough of them! The adults still come around and feed them.  They don’t stay long though, just long enough to drop off the prey, figuring that’s all they need to do.  The chicks have been moving around quite a bit, not going too far from the actual nest.  When we come upon the site, the chicks are apart.  By the end of most days, they are together.  At times it will be the larger chick going to the smaller chick, then the other way around, but generally they end up together.  And its quite fun to watch as they flap their wings, walk like penguin, kind of stiff, shoulders hunched, and then hop to perch wherever it is they want to end up..   

            One day was really exciting:  an adult brought food to the larger chick, the smaller chick was squawking because it wasn’t getting any of the cottontail that was left.  Just as the small chick started to make its move to go ‘steal’ some food, an adult, not sure it was the same one, came and brought another cottontail so that both chicks had some food.  There was a bit of flapping of all wings when this occurred. 

Its been interesting to see how, when the sun is so hot, as it has been some days, they look for shade.  With the sandstone outcrops they can usually find it.  If only they hadn’t left the nest, they’d not have to seek out shade.  One thing that we’ve found is that the smaller of the 2 chicks seems to be doing most of the ‘exercising’.  It likes to walk around.  Either going to the other chick or just exploring another part of its territory.  It doesn’t sit still too long, unlike the large chick.  It likes to stand on 1 leg.  I can see the band on its right leg and when I do see the large chick perched, I can see its band on the left leg.  They do stretch them out when lying down at times to where you can see them stretching their talons.   

Report from Susan Ahalt and Nicole Suuck on 11 July – very typical of nests still active:  Both babies were in the nest and looking more alike and very much the same size now.  Both parents were there when we arrived.   We’d never seen any flapping from the babies but today they each did some, more like keeping their balance than building flight muscles.   I keep thinking they’ll fledge soon but at this point it may be the end of next week.   It was very hot today but we passed the time in pretty good shape.   The deer flies were out, so bug stuff was used as was sun screen.  We both wish to be there when the babies take their first flight and only hope that will happen on our watch. 

This young eagle weighed nearly 10 pounds! Photo by R. Jones

Many thanks again to all of our Posse members.  I can’t include all of your reports each week, but I do read them all and look forward to following your progress.  Just a reminder, your data sheets and field journals are due when your adopted eaglets fledge.  That will be soon for some of you!  Stay tuned for further updates next week.  Best wishes, C. R. Preston

Dr. Preston with recently captured and banded juvenile eagle. Photo by R. Jones

Dr. Charles R. Preston, Senior and Founding Curator, Draper Museum of Natural History At the Buffalo Bill Historical Center in Cody, Wyoming

06 July – Summer seems to have disappeared after only a week or so! Today, we have rain, with high temps in the 50s. Many of our birds are beginning to successfully fledge, and a few have left their nests before being able to fly.

These birds will stay in the vicinity of their nests, and barring predation, human interference, or exposure, the parents will continue to provide for them until

they are able to fly away from the nest area.  I was able to capture and band a couple of these birds last week, and as of today they are still doing well in protected areas under the nest.  These two were just too big to share the nest platform any longer.

Richard Jones completed his aerial survey last week.  We will do some ground-truthing later this week, and I’ll compile our results for you next week.  Although nest occupancy was down considerably this year, the success rate productivity of occupied nests appears to be higher than last year.  An analysis of weather data and relative prey abundance during the past two years may help us understand the year-to-year variation in nest occupancy, success, and productivity.  It will be especially interesting to relate landscape composition and human activity with nesting dynamics as our study continues.  Will eagles demonstrate significant prey-switching behavior as our robust rabbit populations begin to decline, or will there be a significant reduction in nesting effort and success?  Are prey and vegetation characteristics different in areas of the Bighorn Basin where nesting eagles are absent?  These are some of the questions we will be addressing as more information becomes available.

Nest 1A after single eagle fledged last week. There are at least three deer legs and part of a cottontail carcass in the nest. photo by C.R. Preston

Here are some of the reports I received this past week from our Golden Eagle Posse nest monitors:

Report from Anne Hay and Richard Gruber on 01 July:  We had an interesting day at the nest, with enough activity to make the 6-hours move by quickly.  Our oldest chick was seen exercising its wings a number of times while jumping from one side of the nest to the other.  I suspect this one will soon fledge.  The youngest chick, however, has a lot of spunk.  One of the adults flew in with a small rodent, and both chicks pounced on the parent, so that it looked like a ball of eagles.  Seconds later, when the adult flew away, the youngest chick was mantling the prey.  The oldest chick did not put up any challenge for the rodent, and after standing near the smaller, mantling chick for a short time, just moved to the north side of the nest.  The youngest chick then picked up the rodent by its long tail, and moved quickly to the south side of the nest, where the rodent was quickly eaten. Besides this prey delivery, there was also some type of prey already in the nest when we arrived that both chicks took turns feeding on, and later in the morning an adult flew in with a medium sized prey that was actually fed on mainly by the adult, as the chicks looked on.   

Report from Richard Brady on 01 July:  I checked the nest with my scope and looked around the area with binocs but no bird was to be found!  There were the usual pigeons and what appear to be swallows flying around but all at once I saw what I thought was an adult bird doing the circle the valley below, so I noted the time

This nestling in the northern zone of our study area will soon fledge. photo by R. Brady

and wrote that down!  When I looked back up there was a bird sitting on a ledge high point looking around!  I moved the scope from the nest to this bird to find out that this is our last chick which I believe is a boy bird given its smaller size!  This bird walked to several other perches while I was there and when a breeze blew on him there was still some white feathers to be seen!  I stayed the full 2 hours watching this bird but it just sat looking around at other small birds and sort of weaving..>has to be our guy!!!!

Finally, a report from Rosemarie Hughes on 04 July:  As I drove up I saw an adult flying away from the nesting area.  I didn’t get a chance to see if it was with the chicks or not.  When I was in position, I could hear lots of chirping from the smaller chick.  The large chick wasn’t even close – I had to look around.  Couldn’t see it so drove a little closer.  There it was, about 10 feet east of the small chick and the landing.  The large chick was sitting in front of some food.  I could see the red of the meat plus a little something hanging from the beak.  I lost sight of the large bird.  I knew it didn’t fly away or roll down the hill.   At this point the larger chick looks almost like an adult – from the backside anyway.  Really dark.  There was lots of movement today.  The small chick walking along the landing, the large chick actually flapped and hopped itself back to where the small chick is so they are together, at the end of this day anyway.  Both in the hot sun.

Many thanks again to all of our Posse members.  I can’t include all of your reports each week, but I do read them all and look forward to following your progress.  Just a reminder, your data sheets and field journals are due when your adopted eaglets fledge.  That will be soon for some of you!  Stay tuned for further updates next week.  Best wishes, C. R. Preston

Dr. Preston asnwers questions for field trip attendees on Saturday

Dr. Charles R. Preston, Senior and Founding Curator, Draper Museum of Natural History At the Buffalo Bill Historical Center in Cody, Wyoming

28 June – Summer has finally arrived in the Bighorn Basin!  Temps have climbed to 90 degrees plus for a couple of days, now, and vegetation is beginning to fade.  Last week, however, was peak blooming period for larkspur and globemallow in much of the Basin.  Pronghorn fawns were seemingly everywhere last week.  A few of our Golden Eagles have now fledged, and I expect several more to leave the nest during this week.  We’ll know more after Richard completes his aerial survey later this week.

Larkspur is in full bloom in the Bighorn Basin. photo by J. McDonald

Jennifer McDonald and I led our Eagle Field Expedition (public education program) on Saturday the 26^th.  Our participants were able to observe the two chicks on nest 23A and compare them with the older chicks still in nest 60A.  We also visited a Red-tailed Hawk nest in a large cottonwood tree near highway 120.

Field Expedition participant Wendy Johnson took this photo of the hawk nest through the spotting scope.

The two adults put on quite a show as we watched from about 300 meters from the nest.  While we were watching the three active chicks in the nest, we spotted one of the adults about 200 meters north of our position.  It was feeding on something on the ground and being mobbed by Red-winged Blackbirds and a persistent Western Kingbird.  Suddenly, its mate began calling from a lofty, Cliffside perch nearby.  The two Red-tails then flew around one another and perched for awhile near their nest – still being harassed by songbirds.  Our field trip participants gained a new appreciation for the aerial maneuverability of these birds.  In fact, this was a life-changing experience for some of our participants who are now hooked on watching raptors and other wildlife.  Many indicated an interest in joining our Golden Eagle Posse to monitor one or more nests next year.

In addition to the aerial survey this week, we’ll be conducting our monthly rabbit roadside surveys to help us document changes in rabbit numbers from place-to-place and time-to-time.  This should provide us with a broader context for interpreting variations in eagle diet.

Here are some of the reports I received this past week from our Golden Eagle Posse nest monitors:

Report from Sharyl McDowell and Richard Brady received on 25 June:  A quiet week at nest 38a.  Both chicks are still in the nest – the #1 chick is all dark brown except for an occasional white feather that peeks thru.  Even his under wing feathers are rapidly turning brown.  Boots, head have changed colors.  The #2 chick which used to be the smaller of the two is now almost as large as chick #1.  Has a few more white feathers left on the body, still a number under the wings, and his head is lighter. 

These two eagles should be leaving their nest in the northern zone of our study area soon. Photo by R. Brady

Both chicks flap their wings and hop when they want to move around the nest. We’ve been watching them for 42 days now and they were hatched before  we made our first observation..so they should be close to the magic 51 day mark by now.  PS – the pigeons still survive!!

Report from Rosemarie Hughes and John Ross received on 25 June: Our chicks are sure getting big – I’m not looking forward to the day they fledge, I enjoy watching them too much.  We heard some chirping coming from the nest and the next thing we knew there was an adult flying into the nest, with a cottontail.  We could actually see the bunny ears.  The larger chick immediately laid on it.  The small chick just kept chirping, probably in hopes of being fed.  We didn’t know it at the time but the chicks are feeding themselves now.  Last week we weren’t too sure, thought they were just mocking the adult.  It was kind of funny how their feeding schedule went:  the small chick fed itself for 15 minutes while the large chick stood-by; the next 15 minutes the large chick fed while the small chick stood-by; the next 15 minutes the large bird fed while the small chick stood-by.  One time when the small chick was feeding, the large chick tilted its head as if it wanted to be fed.  We laughed.   They both fed for 40-45 minutes time then they were done.  We saw an adult perched above the nest.  We weren’t sure if it was the same one that was in the nest.  While it was there a pair of kestrels where swarming overhead, dive-bombing it, and giving it the business.  Must have been a nest close by.  The adult just hung in there though.  It probably figured it would get attacked if it flew away so it waited until the kestrels were gone before it moved on.  

These young eagles are still about two weeks from fledging. photo by R. Hughes

Report from Bud and Dale Schrickling on 28 June:  When we first got set up this morning it was difficult to tell if both chicks were there or only one. As the sun rose higher and it got brighter there was only one laying outside in the nest. Our nest has a protected area that we refer to as a cave that the other chick may have been in, but as the light improved and time went on it was apparent that there was only one chick in the nest. As to which one it was that fledged first we can’t say for sure but our guess is it was the older one. Normally we can compare but with only one there that’s not going to happen.  As of Friday they were both still in the nest, so it happened sometime this weekend. The unfortunate thing is that we did not see either the fledgling nor the parents this morning.    

Many thanks again to all of our Posse members.  I can’t include all of your reports each week, but I do read them all and look forward to following your progress.  Just a reminder, your data sheets and field journals are due when your adopted eaglets fledge.  That will be soon for some of you!  Stay tuned for further updates next week.  Best wishes, C. R. Preston

On her way to her observation post, one of our Golden Eagle Posse members ran across this cougar track. photo by A. Hay