Today’s batch of photos comes from Kevin Krebs, who’s been busy banding birds in south-central British Columbia. Kevin’s captions and IDs are indented, and, as always, you can enlarge the photos by clicking on them.
Since 2018, the Vancouver Avian Research Centre (VARC) has been involved in Bluebird Box Monitoring around the city of Merritt in south-central British Columbia.
Like almost all birds, bluebird numbers have been declining, and we’ve recruited many volunteers to maintain and monitor over 400 nest boxes.
A few weeks ago, I had the opportunity to join some compatriots checking nest boxes and banding bluebird nestlings.
Mountain Bluebird (Sialia currucoides)
Mountain Bluebirds (Sialia currucoides) are found throughout Western and Central North America. The males are a brilliant cerulean blue that is almost impossible to capture in a photograph. Imagine a small piece of the most vibrant blue sky you’ve ever seen growing wings and flying free.
They’re medium-distance migrants, with some breeding into Alaska, and wintering down into Northern Mexico. They are cavity nesters and rely heavily on old woodpecker holes, often facing significant competition. North American Breeding Bird Survey (BBS) data from 1970–2014 shows an estimated overall population decline of 21%. Recent research suggests a more complex picture, with some populations declining, some stable, and some increasing.
Next box and Mountain Bluebird eggs
On the left, an example of our nest boxes. Most are located on fenceposts, while a handful are placed on trees and stumps.
On the right, an active Mountain Bluebird nest with four eggs. Their nests are made of dried grasses beautifully woven into a cup, with a few feathers often mixed in. Their eggs are pale blue and slightly glossy.
Tree Swallow (Tachycineta bicolor) eggs and young nestlings
In addition to Mountain Bluebirds (and rarely Western Bluebirds (Sialia mexicana)), these nest boxes are frequently used by Tree Swallows (Tachycineta bicolor).
Somewhat similar to bluebird nests, Tree Swallow nests feature significantly more feathers in their construction. On the left is a nest with eight eggs — matte white and much smaller than the bluebird eggs (my fingers give a sense of scale).
On the right: a nest with six very young Tree Swallow nestlings.
Tree Swallow nestlings
Another Tree Swallow nest with at least six older nestlings. Their eyes have yet to open, so they’re probably only a few days older than those pictured above. The comically large and bright mouths are selected to draw as much attention from their parents as possible, ensuring they get fed.
Adult Tree Swallow
An adult male Tree Swallow (Tachycineta bicolor) who started out as one of those little eggs.
Northern House Wren (Troglodytes aedon)
Another bird that occasionally uses these nest boxes is the Northern House Wren (Troglodytes aedon). There’s no mistaking their nests as they have a profoundly different style of nest-building, packing nearly the entire box with dozens of twigs.
On the right, a peek into the nest revealing the feather-lined cup with seven mottled eggs.
Mountain Bluebird nestlings
This is what we were looking for: Mountain Bluebird nestlings. These birds are 9-10 days old, making them old enough to band. We can’t band them when they’re much younger as they store fat in their legs, making them too large for the metal bands we use.
Banded Mountain Bluebird nestlings
Two Mountain Bluebird nestlings in the hand.
Before anyone panics: yes, I am trained to do this and am operating under a permit! I don’t think I need to tell any of you not to try this yourself.
The bird on the left is around 12 days old, while the one on the right is approximately 15 days old — probably within a few days of leaving the nest.
Note that we use federally numbered bands, anodized with a different colour for each year. This allows us to identify adult birds to the year they were banded, even if we can’t get the band number.
Banding in progress
A photo of me in the process of banding some nestlings. The bags on my lap contain birds to be banded and that have been banded. Once they’re all completed, we carefully and quietly place them back in the nest box.
Not pictured is when I sat directly on top of an ant nest while getting ready to band…
Very interesting work that you are doing. And, great pictures!
This was very interesting! And the pictures are great.
It’s also interesting that tree swallows use the feathers of other – and seemingly much larger – birds to line their nests.
Very interesting! I so much admire this important work.
Thanks
Thanks for a wonderful post and photos. Glad to see VARC is doing great work for those gorgeous Mountain Bluebirds.
Very nice. I have a bluebird nestbox on my property west of Fort Worth, Texas, and this year they have nested twice. The first time they fledged five and just last week they fledged an additional six. I wasn’t quick enough to remove the first nest; so they built another on top of the first. I guess they don’t like reusing a dirty nest. I just yesterday removed both nests; so we’ll see if they nest a third time. The only time they did that was a few years ago, and none of the third set of eggs hatched. They are Eastern Bluebirds, by the way, (Sialia sialis.)
Love those little youngsters who are all mouth!
As others have said, best wishes on your important work.
Thank you. We have most of these species here in the Tetons, too. Fun to see the work you do with them.
Thank you for this interesting post. I have 3 boxes on my property and they are used (at different times) by Eastern bluebirds, wrens, tree swallows–and the house sparrows keep trying. The box they fight over is the one only 15 feet from my front door — perhaps because the presence of people and dogs keeps the predators away. Or should. But this summer the bluebird’s first nest was destroyed by the house sparrow. I googled solutions and built a ‘spooker’ made of a wire hanger and foil ribbons that has since kept the sparrows away. The bluebirds raised six nestlings — but something seems to have happened when they fledged because the next day I found the box empty of the babies but the male inside injured and dead. The female was sitting on top of the box and wouldn’t leave until I removed his body. Was she mourning? It certainly broke my heart.
I got curious when bird banding started and got this quick AI dump:
Bird banding developed through centuries of early tracking, evolving into a formal science in 1899 when Danish schoolteacher Hans Mortensen placed numbered aluminum rings on birds. In the U.S., it grew rapidly after Smithsonian scientist Paul Bartsch banded Black-crowned Night Herons in 1902.
I was expecting 1940s earliest.