Friday, 17 October 2014

Trumpeter Swans – Yellowstone National Park

Yellowstone has many well-known and iconic animals such as bison, once down to only 20 or 30 in number, but now numerous and easy to find roaming in herds across the open grasslands. Wolves, another iconic species, have been reintroduced to Yellowstone, but are not easy to see. 
For avian fauna in Yellowstone there are probably no iconic species that one would look for in the Park that could not be found elsewhere. For me however the Trumpeter Swan was one species I was hoping to see in the Park as a small permanent population lives there year round. The local birds are joined over winter by some migrating birds coming down from Alaska and Canada, however as we were there in early Fall we would only have a chance of seeing the resident birds.
The Trumpeter Swan was almost wiped out from the lower 48 States by the early 1900’s and severely reduced in the remainder of its range in northwest Canada and Alaska by hunting for food and feathers, (its large flight feathers made high quality quills apparently), habitat destruction and lead shot has poisoned many young swans. With protection and careful management the species has now made a recovery in its core range however the resident population in Yellowstone has been in decline for a number of years now.
The Trumpeter Swan (Cygnus buccinator) is only found in North America though it is closely related to the Whooper Swan found in Eurasia – some authorities regard them as the same species. It is the heaviest bird native to North America and, on average, the largest living waterfowl species. An all white plumaged swan, the Trumpeter may be confused in the field with the similar but smaller Tundra Swan.
We found Trumpeter Swans by luck when a road closure forced us to go the long way round to visit Old Faithful. The road took us along a section of the Yellowstone River at the northern end of the Hayden Valley where the river widens and flattens into a slow shallow course before its dramatic plunge through the spectacular Yellowstone Grand Canyon.
Yellowstone River, Hayden Valley, Yellowstone National Park, a great wildlife viewing area.
First fall on Yellowstone River downstream from Hayden Valley in Yellowstone Canyon.
As usual we were alerted to the presence of some wildlife of interest by a large crowd gathered beside the road along the riverbank, including at least a dozen photographers, some with very long lenses on tripods. It was not until we stopped, got out of the car and walked over to the top of the river bank and looked down that we discovered the wildlife species of interest, in this case, two adult Trumpeter Swans feeding on aquatic vegetation right beside the river bank.
Just a few of the large lenses focused on a pair of Trumpeter Swans.
To frame these two large swans the long lens contingent were forced to station themselves well back however with my shorter (420mm) lens I positioned myself closer. I was soon joined by at least six other photographers gathered close beside me and was surprised to hear the large bursts of shots they were firing off for two such large slow moving birds. To capture action shots, for example birds in flight, I sometimes use the Continuous Shooting mode, which I generally have selected and control with the shutter button for single shots or bursts as needed. For me this situation demanded careful attention to detail and capture of shots here and there when appropriate and not rapid firing with large numbers of images captured.
Two adult Trumpeter Swans on Yellowstone River. The shallow section of river in the Hayden Valley provided good habitat with aquatic vegetation to browse.
Adult Trumpeter Swan, note the straight bill and the black facial skin tapering to a V at the eye.
The duck was feeding on tit bits disturbed by the Swan.
The adult swans were active pulling up waterweed from the bed of the river and eating, stirring up mud and other matter as they foraged. A few ducks were scavenging close by for tit bits stirred up by the much larger swans. Feeding associations among birds such as this are quite common.
To my surprise three ducks were huddled together sound asleep beside the bank with a large number of tourists and photographers standing directly above them and birds feeding nearby. Clearly these ducks felt safe in Yellowstone.
Sleeping ducks.
After capturing a few shots of the adult birds feeding I noticed four more swans about 100 metres downstream. A quick scan with the binoculars showed them to be three juvenile Trumpeter Swans and what looked like one white adult. The four commenced to swim upstream towards us in close formation.
Four Trumpeter Swans making their way in V formation upstream. The three grey birds are juveniles, the white one does not have an all black bill?
Before the juveniles arrived the two adults lost interest in feeding and moved off to commence some preening, giving the opportunity to capture a few shots of one with its wings spread while flapping to arrange and settle preened wing feathers.
The two adults were preening when this one began to flap its wings.
I guess vigorous flapping of the wings shakes out any dirt and loose feathers and helps
to arrange and settle the wing feathers.
The Trumpeter Swan is the largest waterfowl, adult wingspan exceeds 2 metres.
As the juveniles approached I noticed that the white bird was also juvenile as it had a largely pink bill and not a fully black bill. A later check of field guides showed this was a rare white juvenile which are only found in the Yellowstone birds.
I suspect the four young birds were siblings belonging to the two adults. All four young were banded.
The young ones arrived below us and commenced feeding where the adults had recently left off. As with many young, they fed close together even though there was plenty of space and food for all and the inevitable squabbles broke out with some feather biting and so on.
Three of the four juveniles feeding close together.
The rare white juvenile is letting the typical grey juvenile know it is too close.
There has been a lot of research on Trumpeter Swans in Yellowstone to try and work out why the resident population has been declining since the early 1960’s. Anyone interested in this subject can find links to papers on the topic in Wikipedia; just enter Trumpeter Swan in the Wikipedia search box.
All four juveniles were banded, this is H53.
I hope H53 and his/her siblings enjoy a long and productive life in Yellowstone and that there will always be a resident population of Trumpeter Swans there for future visitors to see and enjoy as we did in the Fall of 2014.