As summer progresses, the birds are really finishing up their nesting season. We banded our last nestlings for the season at the end of July. The very last box banded was in the Davis Nestbox Network in north Davis – a brood of western bluebirds, the second successful nesting attempt at that box this year!
I’d like to give a huge thank you from me to the rest of our small nestbox crew and helpers this season: Estefania Maravillas, Monica Burnett, Danielle Fradet, Michelle Mah, Alison Ke, Melanie Truan, Isabella Calcatera, Doris Wu, Andy Engilis Jr, and Irene Engilis. Together we managed to keep up with banding and data collection to get a good record of the nestbox activity this season despite this year’s challenges. Thanks for all of the hard work!
Below is a sped-up video by Danielle Fradet from up at Bird Haven, banding the last box of nestlings there (ash-throated flycatchers) in mid July. (Click the image below to view the video on the MWFB Instagram page!)
Almost all the songbird nestboxes were used this year. At Russell Ranch a few weeks ago, one tree swallow pair seemed to be using a duck nestbox too!
Earlier in July, Dr Kevin Keel spotted one of our banded adult tree swallows at Lake Solano. He sent along the lovely photo below. This bird was most likely banded one or two years ago in Winters.
Now we only have a few boxes to check to see if they fledged successfully this week and the next. We’ll be switching to mostly indoor work with the data again now that the breeding season is done. It will be nice to be out of the hot weather more, but I hope to still see young songbirds around nearby.
There are a lot of young birds out and about lately along Putah Creek and elsewhere. Most of the nestlings have fledged by now, but they often stick around their old nestbox areas for a while. You might see them at the various parks along the creek in Davis and Winters, and they may be wearing our color bands on their legs, like this fledgling seen by Mary K. Hanson.
The color bands allow us to find the bird’s information in our records, including where and when it was banded among other details. This fledgling, like most young western bluebirds, also has many little white spots on its back and breast, as well a wide yellow gape along the sides of its bill. These are all indicators that this bird is less than a year old. Another way to tell is if the bird receives food or begs from another, though this bird has started finding its own food.
We are still waiting for some eggs to hatch in our nestboxes. Bluebirds, tree swallows, and ash-throated flycatchers are still active along Putah Creek and in the Davis Nestbox Network at various stages of nesting. The weather has been pretty nice and the birds seem generally healthier overall than last year. We’re looking forward to seeing more fledglings soon!
New eggs are being laid in many of the nestboxes as our birds start their second nests or get a late start. Meanwhile there are always at least a few birds that are old enough to be banded each week. Ash-throated flycatchers are still in the middle of their main nesting season, which is usually shorter and later than it is for our more common nestbox species (tree swallows and western bluebirds). House wrens seem to be done raising nestlings this year on Putah Creek.
It’s consistently hot here in the middle of the day lately, so our crews usually work in the mornings to beat the heat. Though it won’t be as busy as May, the banding season continues!
Many new hatchlings are expected to appear along Putah Creek again soon. There are currently over 40 nests with eggs all the way from Interdam (near Lake Berryessa) to Mace Boulevard in Davis. Bluebirds, tree swallows, house wrens, and ash-throated flycatchers are all still taking care of new and old nests along the creek.
The Davis Nestbox Network boxes have been put to good use by western bluebirds and tree swallows. So far 75% of the nestboxes there have been occupied this year. Only a few boxes currently have eggs or chicks now after the main wave of nestlings in May.
Our Bird Haven nestboxes have been very productive again this year as well. House wrens and ash-throated flycatchers are still fairly busy up there producing eggs and chicks. 26 broods have been banded so far, and there are now about seven new clutches of eggs.
The weather will continue to be pretty nice this week, so hopefully the birds will stay healthy and comfortable.
It looks like we’re just about to head into the usual lull in the banding season. The busiest part of the season is mostly over, but there is usually another smaller spike in nest activity a few weeks after that. Western bluebirds often have second or even third broods of chicks after the first ones fledge, and ash-throated flycatchers are producing their eggs and nestlings now.
We’re in the middle of the busiest part of the nesting season. Lots of nestlings are hatching, growing, and fledging right now, meaning we have to keep track of boxes to band and boxes to leave alone. Once chicks are big enough, we give them metal and/or color bands, and then wait a couple of weeks for them to leave the nest undisturbed. Even though there’s a lot to keep track of, this is my favorite part – seeing lots of baby birds growing up.
I also want to show how egg color can vary in bluebirds. We usually see bright blue eggs, but now and then the eggs are white! Earlier this month I found a nest with bluebird eggs that were almost completely white. They’ve since hatched into healthy chicks that I banded recently in Winters.
Have a nice Memorial Day weekend everyone, and stay safe!
Right now our nest boxes are showing a good range of the different stages of the nesting process. We’ve begun to see more boxes with little Western Bluebird and Tree Swallow chicks!
The rest of the boxes vary from having just a few twigs as the parents begin building their nest, to having a couple eggs as the rest of the eggs are still being laid, to having the full clutch of warm incubating eggs. The majority are incubating now, so I’m excited for the nestlings that will be hatching soon.
In other exciting news, we have seen Ash-throated Flycatcher nests appearing in the boxes at Russell Ranch and in Winters, and some already have eggs.
Our nestboxes have a lot of eggs now, and many more nests! The Putah Creek nestbox trails from Winters to Davis all have active nests – tree swallows, western bluebirds, house wrens, and white-breasted nuthatches. The nestboxes in North Davis and up at Bird Haven are also very active. Within the next couple of weeks, a lot of eggs are expected to hatch, and soon after that we’re likely to begin the busiest wave of nestling banding this year.
Nests in Winters near Dry Creek. Top left: western bluebird nest. Top right: tree swallow nest with a lovely variety of feathers. Bottom: tree swallow nest with two eggs!
We don’t have any ash-throated flycatcher eggs yet, but we’ve observed adults around the creek, and I saw a pair together at one of our Winters sites. I hope they’ll have another good season.
A lot has changed in the past month, but we’re checking nestboxes again! (If you’re reading this later, the COVID-19 shelter-in-place orders have recently halted or changed a lot of things in Davis and of course around the world.) We’re sadly not able to have groups of students out with us this season, and we really miss their help and their energy. However, our limited nestbox crew is doing a great job monitoring nests so far while keeping our equipment sanitized. We’re even beginning to band some nestlings.
White-breasted nuthatch nestling, one of our first nestlings this year. Photo by Estefania Maravillas
Our first banded nestlings this year were white-breasted nuthatches in Winters. They tend to nest earlier than our other usual species. Another nest of nuthatch eggs at Russell Ranch will hopefully hatch soon too. There are bluebird nestlings that will be banded soon in North Davis, which has a lot of other nests starting already, and Mace Boulevard has many bluebird and tree swallow eggs right now.
Male western bluebird in North Davis. Photo by Kelli O’Neill
Baby bluebirds in Davis. Photo by Melanie Truan
It’s really nice to be outside again, and I hope we can bring a little of the fresh air into this blog for anyone stuck inside. If you’re able to go take a walk in this nice spring weather, keep an eye out for nests and migrating birds!
The field crew and I have started checking nestboxes for any early nests. We’ve been seeing bluebirds and tree swallows in pairs hanging out near some of our nestboxes already, though the time for building up most nests has yet to come. We’ve been able to ID some previously banded birds by watching pairs that are starting to stay near boxes.
A nestbox in north Davis, waiting for the right tenants
It’s also a good time to clean out any boxes occupied by wasps or rats. Removing unwanted species from boxes is a somewhat unpleasant but important part of prepping for the songbird breeding season. Wasps are a pretty common issue for our boxes. We try to scrape them and their nests out early in the morning while it’s still cold and they’re not very active. Rats are less common, but usually dealt with pretty easily. Boxes with leaf nests (not built by birds) are emptied carefully, allowing hiding rats to jump out and run away. They seem to mostly stay out once we evict them early in the season. Sometimes wasps also hide in rat nests – those are my least favorite nests!
We’ve restocked all our field work supplies for the season too. Hopefully we have more than enough bands for the many new birds we expect to find.
Some of the color bands that will be put on birds’ legs this year