By Elaine Caton, Trumpeter Swan Restoration Program Coordinator
This past spring saw quite a few days of cool, wet weather in the Blackfoot, which seemed to affect our swan productivity this year. There were six known nesting attempts, five of which were successful, producing a total of twelve cygnets. This is a bit fewer than in the past couple of years, when we had 24 cygnets (2016) and then 20 cygnets (2017) hatch. One nest that has been successful the past two years was actually underwater for most of the nesting season, and the pair did not nest at all.
Since Trumpeter Swans must incubate their eggs for around 34 days in May and June, it can be tough to make sure those eggs stay at the right temperature the entire time, since the female swans must get off the nest occasionally to feed. While the males of some bird species will share incubation duties with the females, in most waterfowl the incubation is solely the job of the females. As long as it is not too hot or too cold, they can leave the nest at times by covering their eggs with nesting material and downy feathers. This insulates the eggs from the weather and also hides them from potential predators. It’s likely that in a cool, wet spring there will be times when that strategy fails to keep the eggs warm enough. In our watershed one nest failed entirely this year, one had only one cygnet, and two had only two each, although the other nests had three and four each.
However, the great news is that all twelve of those cygnets have survived so far! It’s pretty unusual for all that hatch to survive the first few months, and as they get larger they are vulnerable to fewer predators, so the outlook for a healthy number to make it to fledging (flying) age is good.
You may recall that last year we had to cancel the swan release due to wildfire activity and smoke. We were able to release those swans as yearlings this past spring, and planned another public release this September with young swans hatched in captivity in May. However, like our Blackfoot nests, the swans at the facility where they are hatched did not do very well this spring either. Unfortunately, that means they don’t have any young swans for the Blackfoot and we will not have a swan release this fall either.
While it is very disappointing that we won’t have this wonderful fall event for the schools and the public again this year, the good news is that our swans seem to be slowly but surely increasing their numbers on their own. Our monitoring efforts from the ground and a recent survey flight showed 45 adult Trumpeter Swans in the valley along with the 12 cygnets. Most of those “adult” swans are likely one or two years old and have not yet begun to look for a mate and territory. Hopefully they will continue to return to the Blackfoot in the spring and soon be ready to settle down and raise families of their own.