October changes

As bird surveys continue into October, I had the opportunity to go see how the Winters Putah Creek Park is changing. The new plants are growing nicely, giving a better idea of how this site will look next spring when our birds start nesting again.



A banded juvenile bluebird, possibly the same one as in the last post, was seen this past weekend again in Northstar Park in Davis. White-crowned and golden-crowned sparrows are also around Davis in large numbers now that we’re further into fall. Hopefully the birds that are still migrating will be alright through this week’s windy weather.


Juvenile bluebird

Kelli O’Neill recently saw one of our banded bluebirds foraging in Northstar Park, where Alison Ke monitored the new nestbox trail this year. This juvenile western bluebird came from one of those boxes. After checking its leg band combo with our records, I found out that it hatched on about July 17th and was banded on July 30th. It came from a brood of four total nestlings, the second brood in that box this year. Both broods were very successful. It’s great to know that this bird is still doing well and taking care of itself!


Juvenile western bluebird catching bugs in the grass. Its metal and plastic leg bands, partially visible in the photo, were used to identify it. Photo by Kelli O’Neill. 

We’ve mostly been busy looking at our data in the office lately, but we’re still doing avian surveys as the fall migration period continues. I’m looking forward to the cooler weather and hopefully seeing a lot of birds.


Fall migration

Migratory birds have started to make their travels from their breeding ranges to their winter locations. It’s a good time to keep an eye out for uncommon birds passing through and welcome the winter residents back to California. Golden-crowned sparrows, for example, will be heading down here from Canada while yellow warblers will mostly be leaving for Central America.

Flycatchers will also be heading south, including the ash-throated flycatchers that used our nestboxes this year. The rest of our nestbox species will still be around as winter comes, though groups will migrate a bit.


Interdam, one of our nestbox sites on Putah Creek near Lake Berryessa earlier this week

Lately I’ve been seing summer species such as Wilson’s warblers, migrants such as a solitary sandpiper that I saw while with a *Friends of North Davis Ponds group, and what seems like an increase in Canada geese.

Keep your binoculars handy as we get more migrating species passing through!


Recaptures and resights

It’s always exciting to see or catch a banded bird. This year we were able to catch a dozen previously-banded birds, and more were seen and recorded. Many of these birds had hatched last year or the year before, and they often return to the same area where they hatched, at least for the breeding season. However, there was one male western bluebird sighted that apparently moved from Winters to east Davis and was about eight years old!

Other birders often report their sightings to us. Below are a couple of photos by Ryan Bourbour of a banded house wren he saw near Old Davis Road in Davis. It hatched in that area just three months ago. Good to know that it’s still doing well!



Notable recaptured birds this year include two female tree swallows at our Interdam site that were at least four years old, each building nests just one box over from their last known nest. One has successfully raised at least 11 total known chicks so far. We also recaptured a female bluebird named Amanda that used the same box at Russell Ranch for two years. She was at least three years old and has raised at least five chicks that we know of. Captured birds are quickly and gently measured and examined on the spot before we set them free again minutes later.

Many previously-unbanded adult birds were banded this year too. We don’t know if they came from nearby natural cavities or from further away, but hopefully we’ll be able to find out where some of them go from here.


2019 Nesting Season Review

This season brought a number of challenges for the birds, including feather mites, unusual weather, and predators. A sudden cold spell in May seemed to be one main reason for nest failure. Still, 832 birds fledged from the nest boxes this year. As usual, most of these were tree swallows (386), followed by western bluebirds (254), then house wrens coming in third (152). White-breasted nuthatches had more success this year than usual, with 15 fledglings making it out of their nests. The ash-throated flycatchers also had more fledglings than usual (25), breaking the downward trend they had been experiencing in recent years.

Our Winters Park site, where we brought back nestboxes after a hiatus of several years, proved to have at least four previously-banded tree swallows using the nestboxes this year. For some reason, the north side of the creek was much more popular there than the south side, and the only occupants were tree swallows and ash-throated flycatchers.

The Davis Nestbox Network, a completely new site, had just a few active nests as expected for its first year, but they were quite successful and had several second clutches.

We’ll be planning a few changes to the sites over fall and winter. Moving some boxes may help against predators, and we’ll be adding a few more boxes to our smaller sites.



Finished banding

We’re finished with banding for the year! The last bluebird nestlings were banded in Winters last week. (The Arboretum chick unfortunately didn’t make it to banding day.)


One of the last bluebird nestlings banded this year

Now all that’s left in the field are a few fledge checks. I’ve been looking at the last active boxes to see if all the chicks have made it out of the nest. The second camera box, with a nest of four ash-throated flycatchers, was one of the successful nests. It was in a location with more sunshine than the last nest with a camera, so we have a lot of photos in color this time. Below is a series of some of these photos, showing the growth of these nestlings.


Flycatcher nestlings on hatch day, with one egg left to hatch


Nestlings a few days old, featuring a parent


Nestlings at about 1 week old. They were banded four days later.


Nestlings one day before they left the nest

Next week I’ll be done with all nestbox checks until next March, and I’ll be posting some of the final numbers and totals from the 2019 breeding season on Putah Creek!



There are only two more boxes of birds left to band this year — both bluebirds — and about a dozen recently-banded broods that will be leaving the nest soon. Yesterday Alison and I banded bluebirds in the Davis Nestbox Network, a second brood after a successful group of chicks fledged from the same nest. All that’s left to band is a nest with four birds in Winters, and then a single nestling in the Arboretum. The chicks will soon be exploring the rest of their environment and hopefully avoiding the dangers around them.


Trees around Northstar Pond in Davis, where bluebirds have been busy feeding their young.

The remaining inactive nestboxes have been cleaned out to prepare them for next year. Below is an old tree swallow nest with extra lining, including turkey feathers and what I believe are egret feathers, among others.


Tree swallow nest being removed from the nestbox after the end of the breeding season.

I’ve seen a few more fledglings flying around our sites lately. Hopefully we’ll see them building nests next year too.


Putah Creek at Interdam in Winters.