The Ash-throated Flycatcher is a relatively large flycatcher of the West, taking over where its eastern relative, the Great Crested Flycatcher, leaves off. Colorado has a small percentage (1%) of the ATFLs in the U.S.; in this state, they nest predominantly in pinyon/juniper habitat. They are generally late nesters in our area, beginning nest building in mid- to late May. Eggs appear in late May or early June and hatchlings emerge around mid-June. These young really grow up quickly here: If I get to see them at more than 2 weekly checks, it’s a rarity. (In one box this summer, I just happened to catch a nestling as it was hatching and we were able to get photographs for the following 2 weeks as well–what a treat!) Despite their rather large size, they consistently prefer to use the typical bluebird-sized box described on the “Nest box monitoring” page. (You can click on the link in the Pages box to the right.) You can also find information about the natural history of ATFLs by visiting the Sialis Web site.
This year, we had 3 nesting pairs, fledging 6 young. Their nests are easy to identify, even without seeing the parents around (which are, indeed, a rare sight). They are pretty much a clumpy mess of animal hair on top of strips of bark (juniper here). It’s not uncommon to find horse or cow manure in their nests, even though we don’t have many horses or cows nearby–probably within a mile or 2, as the ATFL flies. Here’s a photo of a pretty typical ATFL nest–first, an inside view (where you can see an egg at the bottom of the mirror image) and then a side shot. Click on any photo to see a larger version.
The eggs are also easily identified by their rather large size (compared to the swallows’ eggs, which are typically the only other cavity nester laying at the same time) and heavy brown spotting. Here’s a photo of a nest of eggs.
And this is a photo of an unhatched egg that I found buried deep in the nest after the lone nestling had fledged–again, using that universal size tool, the penny.
Most of the photos of the young are from one nest box that was better situated to catch the natural light than the other 2 boxes. Also, since it had only one nestling that hatched, it was easier to see the characteristics. The dark feathers, in a dark box, made for some challenging photography–especially since we didn’t want to use a flash. Here’s the lone nestling (sounds rather like “the lone gunman”–any conspiracy theorists or X Files fans out there?) shortly after it had hatched. It’s still rather egg-shaped, showing just how recently it had worked its way out of the shell.
Here’s a different nest of 3 nestlings, about 4 days old.
And a last look at the lone nestling at 14 days old. You can see the beginnings of that delightful crest here quite clearly and the gold-streaked feathers on its back are striking. (Actually, I think those feathers are on its wings, which are folded onto its back.) I checked the box the day after we took this photo; the nestling had fledged. So, as I mentioned above, these dudes grow up fast.
We tried very hard to get a good photo of an adult while we were checking nest boxes. It was not a very successful attempt, I’m sorry to say. These birds, at least around their nests, are very skittish and secretive. Before the eggs hatched, the adult (the female, I presume) would generally stay in the box even after had spoken quietly and tapped on the front. As I opened the box, she would explode out of the box at the last second and fly off–usually out of sight. Once the eggs had hatched, it was rare to actually see–or even hear–an adult in the area. Believe it or not, this photo is one of the best views we had of an adult around a nest box. Given the age, I had figured the nestlings might have already fledged; but we were hoping for a photo anyway. As we approached the box, we could hear a loud tapping. A very quick peek into a partially opened box revealed that the tapping was from at least one soon-to-be-fledgling, communicating something somehow. I think the adult was sticking close (using that term loosely) until the kid (or kids) had exited the box.
Needless to say, I quickly closed the box; Zell snapped this profile photo posthaste; and we moved away. The next day, the box was empty–3 new ATFLs happily added to the population from that box!
In closing, a bird bander from CA who has had considerable experience with ATFLs wrote me that ATFLs tend to return to the same areas and select nest boxes within 60-80 yards of the previous year’s boxes. This year, an ATFL pair used the same box that an ATFL pair had used last year. So odds are that that was the same pair–or at least the same female. (The other 2 pairs used boxes in much different areas, so odds are that those were probably not pairs that had raised nestlings on our land last year.)