Tuesday, May 27, 2014

Yellowstone 2014–The Birds!

Here is a continuation of the summary of Karyn and my recent trip to Yellowstone National Park. In a previous post I presented Yellowstone 2014–The Mammalian Predators. This next post is focused on the birds! As a raptor biologist, I probably should have led with the birds, but the purpose of our trip was on wolves so the mammalian predators were posted first.

The Raptors

While there are many birds that I like seeing and many more that I would like to see, there is one particular species that always gets me very excited. Ok, maybe two as I do love to see my study species, the Northern Goshawk, in the wild (we did see two goshawks on our trip!). The species that I am most excited about seeing in the wild is the Peregrine Falcon.

If you don’t know the history, the Peregrine Falcon was threatened with extinction. According to wikipedia, it is the most widespread raptor of the world and one of the most widespread bird species in the world. However, through human actions, this species became threatened with extinction primarily at the hands of a chemical pesticide known as DDT. The impressive part of the story, and the part I am most inspired by, is the fact that humans realized the problem, changed, and the species is now rebounding in many parts of the world, particularly in the United States. We are still dealing with the remnants of DDT in our environment and it’s US manufacturer still ships the product overseas. But it’s decreased use has resulted in the rebounding of Peregrine Falcon populations. It is a tremendous success story. Conservation is most often a bad news business. Many of our actions are simply delaying or slowing the trend toward extinct instead of reversing it. As species across the world head toward extinction, it is still encouraging to know that if we put our actions toward conservation we can make a difference.

On this trip to Yellowstone, Karyn and I spotted two adult Peregrines in flight and observed a nest. I was awed on each occasion.

Peregrine Falcon in flight above Yellowstone River (likely from nest we observed near there).

Peregrine Falcon in flight above Yellowstone River (likely from nest we observed near there).

Peregrine Falcon preening, Round Prairie.

Last year we found a Golden Eagle nest near Slough Creek. We returned to the area this year finding three un-used nest structures. However, we did find an adult in the area eating what appeared to be a ground squirrel and a sub-adult unsuccessfully trying to get in on the action. It is possible the adult and his/her mate have a nest that we did not detect, or they may not be breeding this year. Golden Eagles do not necessarily breed every year.

Sub-adult Golden Eagle, Slough Creek.

We observed two Bald Eagle nests, both occupied. The nest in the Lamar Valley is easily observed from the main road on the opposite side of the valley. We saw two nestlings (chicks) in the nest and observed a feeding on one occasion. The adult Bald Eagles were regularly observed visiting various carcasses.

Adult Bald Eagle flying over elk carcass in Lamar Valley.

Through our travels and past knowledge, we located three occupied Red-tailed Hawk nests. These birds regularly fly over one of the best viewing areas in the Lamar Valley, Dorothy’s Knoll. Each evening, multiple birds are present soaring on the updrafts caused by the breeze through the valley. They often interact with the Ravens and the Bald Eagles.

Adult Red-tailed Hawk flying in Lamar Valley with Jasper Bench in the background.

The Osprey put on a show! We found four nests in the park and one near Mesa Falls, just outside the park. The nest in Lamar Canyon is a highlight as a turnout on the main road provides an above nest view. We watched as one bird returned with a fish, ate half, then handed the rest to it’s mate. They then switched incubation duties as the other finished the dinner.

Osprey prey deliver and incubation exchange, Lamar Canyon.

Just above Upper Mesa Falls on the Henry’s Fork in Idaho, we observed another pair of Ospreys during an incubation exchange. This one did not involve food.

Osprey nest, Upper Mesa Falls, Idaho.

Osprey, Upper Mesa Falls, Idaho.

Last year we found a Great Grey Owl nest. We returned to check on the nest this year and found it unoccupied. We search the area but found no other nests. I hope they are nesting somewhere.

The Songbirds.

Hiking in Yellowstone during the springtime is fantastic as every songbird tries to be heard over all of the others. The forest and shrublands are filled with non-stop songs from the powerful and  warbling Ruby-crowned Kinglet, to the methodic and simple Chipping Sparrow. Sometimes there are so many birds singing at once it is difficult to distinguish one song from another.

The Yellow-rumped Warblers were pervasive in sight and sound.

Male Yellow-rumped Warbler (Audubon sub-species), Tower Road.

Male Yellow-rumped Warbler (Audubon sub-species), Tower Road.

My favorite songbird of the trip was observed at Upper Mesa Falls, outside the park in Idaho – the Green-tailed Towhee. I love this bird for a number of reasons. First, this bird is an important prey species for my research focus, the Northern Goshawk. I am always telling people that you cannot admire the predator without respecting the prey. The inverse is also true, you cannot admire the prey if you do not also respect the predator that helped create and improve it. A few of my co-workers can probably guess my second reason and why I was excited to get these photos. A few years back we captured one of these birds during our banding process. I was processing the bird and fumbled it before anyone had a chance for a photo. These photos are much better than a bird in the hand!

Green-tailed Towhee, Upper Mesa Falls, Idaho.

Green-tailed Towhee, Upper Mesa Falls, Idaho.

Vesper Sparrow, Hellroaring Trail.

Mountain Bluebirds are quite common in the Yellowstone area as there is no logging to remove the dead snags which provide homes for woodpeckers and then bluebird (as well as other cavity nesters). We observed bluebirds on many of our hikes. The blue color can appear dramatically different in different lighting conditions. the next two photos highlight the difference. The first is in late evening sunshine, whereas, the second is in mid-day sun.

Mountain Bluebird, evening sun, Elk Flat.

Mountain Bluebird, mid-day sun.

Mountain Chickadee, Specimen Ridge.

Chipping Sparrow, Hellroaring Trail.

Other Birds.

The sound of Sandhill Cranes rank in my personal top-10 bird sounds. Their calls were heard nearly everywhere in and around the park.

Sandhill Crane rolling eggs in nest, near Floating Island Lake.

Sandhill Crane flying through Lamar Valley.

While watching wolves in Elk Flat, we observed a Dusky Grouse walking very slowly toward us. She carefully placed each step one at a time before pausing. Our observation of wolves quickly turned into a “wolf jam” of people and cars. Regardless, the grouse kept on her journey. She walked right under the car next to us. Once she reached the other side of the car, she flew across the road and into the trees. The total journey took her more than 30 minutes!

Dusky Grouse, Elk Flat.

Another nearly pervasive bird in the park is the Common Raven. It is widely believed that these intelligent birds work cooperatively with wolves to find prey. We as humans use these birds to find wolves and to find carcasses. More than 100 ravens ON AVERAGE feed on a single elk carcass taken down by wolves.

Coyote and Common Ravens picking through the remains left behind by wolves and grizzly bears.

Common Raven Nest, near Junction Butte.

American Dipper nest near Mammoth.

These is one native bird species of North America that generally gains little respect, even from ornithologists – the Brown-headed Cowbird. The Brown-headed Cowbird does not build a nest. This bird lays eggs in the nests of warblers and other small birds letting them take on the effort of raising the young. This most often occurs at the expense of the warbler’s own young. It is believed that this evolved as the cowbirds followed the migratory herds of North American Bison. They did not have time to stay in one place and raise young. Historically, this had little impact on warbler species overall as only a small number of nests were parasitized and usually only those in poor habitat near the edge of forests. With modern day development, wide-spread cattle grazing, non-migratory cattle operations, forest fragmentation, etc., it is believed that a much higher percentage of warbler nests are parasitized. Hence in people’s perceptions, the cowbird has shifted from an innovator eking out a living creatively to a conservation threat to many species.

In Yellowstone the cowbird does what it had evolved to do, follow bison as they migrate up and down the Yellowstone and Lamar rivers.

Flock of Brown-headed Cowbirds surrounding Bison and calf.

I’ll have at least one more post in this series, so check back soon.

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