ATFL nests!!!

Hello! I’m Alice, one of the Field Coordinators for the Putah Creek Highway Internship this year!

I’ll start by saying that although Russel Ranch is a beautiful site, it can be tricky to check boxes along because it has a lot of very steep hills. I was trying to locate a box near a particularly steep slope when I slipped down and lost my phone 😦 While scouring the dry vegetation-covered slope for my phone and mentally preparing to have lost it, I spotted the box! (don’t worry, I ended up finding the phone later)

The fall was worth it! I opened the box to reveal…. an Ash-throated Flycatcher nest, lined with fur, and a single speckled egg. While I was sitting down trying to dump the dirt and pick the grass seeds out of my shoes, I checked a nearby adult bird’s call on my app (Merlin ID) to confirm it was an Ash-throated Flycatcher. The bird started responding to the calls played by my phone!

There were only the small beginnings of an ATFL nest last week, and now there are 3 beautiful, ready-to-go nests and even an egg!

Along the creek, there were a couple really full House Wren nests. Each were equipped with a territorial adult who sang their angry, bubbling song at me once I got too close. House Wren nests are made of sticks, and the nest cup can be very deep in the jumble of sticks. Counting eggs in these nests takes a combination of feeling around carefully and using my phone as a flashlight/periscope. The latter method results in weird in-the-nestbox POVs like this:

Most of the nests on this site either have eggs or should soon. It’s a pretty late nesting season but the birds are definitely active!

Last but not least, a Tree Swallow in an unused Wood Duck box. Always a nice surprise.

– Alice

Eggs and First Chicks! Plus Other Putah Creek Critters

The nest boxes have been busy this past month, and there are now more than 50 active nests with at least one egg each along the Nestbox Highway! Nestlings have hatched at a few sites, and banding season has slowly started. We had just one White-breasted Nuthatch nest this year, earlier than the other species as usual, but it had eight healthy nestlings all at once!

The Davis Nestbox Network crew in north Davis already has chicks in half of their boxes. They’ve already banded a couple of bluebird nests. Up in Bird Haven, there are lots of House Wren nests with eggs that will be hatching pretty soon.

This year on Putah Creek, in addition to the Nestbox Highway, we’re continuing Jessica Lin’s bat acoustic monitoring project and recording bat calls for many nights each month. We’re just starting to look at this year’s data so far, but we’re seeing a nice variety of species. We also have mammal camera “traps” set up that take photos when motion is detected at bait stations. The photos are pretty entertaining — here are a few below!

We’ve gotten more reports of our banded birds being seen again at spots along Putah Creek, and we’re seeing banded birds coming back to make nests in the nest boxes. Below is a nice male Western Bluebird seen and photographed at the Arboretum by Karen Bos earlier this year. Since all four of his bands are visible, I was able to find out that this bird hatched two years ago at the Arboretum. Hope he makes a nest there this year!

Male Western Bluebird with color bands in the UC Davis Arboretum. Photo: Karen Bos


First Nests

I’ve finished most of the nest box cleanup, repair, and replacements at each of our sites now. Good thing, since there are already a few nests being built! Western bluebirds, tree swallows, white-breasted nuthatches, and house wrens have started nests in a few boxes, bringing nesting material inside and staying nearby. I also saw a few nasty but impressive aerial battles over nest boxes recently. I made sure any rats, wasps, and house sparrows left the boxes they were using, but we’ll still have to make sure they don’t return.

Western bluebird nest at the Picnic Grounds mid March 2021, just about ready for eggs!
Photo: Hanika Cook

We’ve had a little rain (and hail!) lately, but the water in Putah Creek is still pretty low for spring. It looks like it’ll be a dry year.

Putah Creek at the Picnic Grounds mid March. The water looks similarly low at the Winters sites, and it looked about this low today too. Photo: Hanika Cook

And as expected, many nest boxes along our Nestbox Highway had to be repaired or replaced after years of weathering, or just determined woodpeckers or a windy day as the case may be. Thanks again to Ron Ringen for the fresh batch of nest boxes he’s made for us this year. Several other nest box trails have been springing up in the area too, and I wish them all happy monitoring and a great spring!

Nest boxes from Ron, ready to hang up along the creek. Photo: Hanika Cook


Birds Near Nest Boxes

Tree swallows flying near a nest box at an orchard by Putah Creek in Winters.

We’re seeing birds starting to check out nest boxes and stay near them. Above is a small group of tree swallows (flying, in the center of the photo) that I saw swooping near this nest box in Winters. I’ve seen bluebirds behaving similarly in Davis recently too. Our records indicate that the birds that use our nest boxes have been starting a bit earlier each year. We’ll check all of our boxes soon in March to repair and replace them, and record any early nesting activity. Many updates ahead!


Preparing for the 2021 Nesting Season

2021 has begun, and we are already starting to prepare for the coming Spring. There’s no telling yet what the weather will be like between now and April, but there are already a few nest boxes that will need to be replaced along the creek due to the fires last year along with the usual wear and tear. We’ll also need to restock our bands and other supplies. If conditions are right, we expect to have even more nestlings to band this year than last!

A trail close to our nest boxes near Old Davis Road, January 2021. Photo by Hanika Cook

It will be exciting to see what this year brings for our nest boxes and birds at Putah Creek and beyond. I was birding recently in Davis and saw many bluebirds without bands near our nest boxes. They could be newcomers, or they might be locals that hatched from natural cavities. We also continue to get reports from Davis and Winters residents on banded birds that have been re-sighted, which are a great addition to our data on the birds’ movements and survival. It’s always nice to hear from these folks and exchange bird info.


Aftermath of Fires at Putah Creek

We have recently learned that the LNU Lightning Complex fires have had an extreme impact on the landscape along the stretch of Putah Creek from Lake Berryessa’s Monticello Dam to near Lake Solano. This includes Interdam, one of our long-standing nestbox sites. Sadly, that site has been extensively burned.

But this image sent to us by John Hansen shows us a ray of light: At least one nestbox was still hanging! This box has housed successful tree swallow nests in recent years, with five fledglings in 2018 and four in 2019. Recently, after the fire, several bluebirds were seen in this area, showing another glimmer of hope for the local birds.

Photo: View of a burnt landscape next to Putah Creek, with some charred trees standing and visible ash on the ground. In the top right corner of the image hangs a wooden songbird nestbox on a tree branch, apparently undamaged.
Nestbox found still hanging (top right area of image) at Interdam after the LNU lighting complex fires. Photo by John Hansen.

I have not yet explored Interdam after the fire, but I plan on looking for any other remaining nestboxes. The nestboxes themselves can fairly easily be replaced, but I hope the burn area can still support a variety of bird and wildlife species as the vegetation slowly recovers.


2020 Nesting Season Review

The nestbox season is well over, and I’ve been spending time organizing and looking at this year’s data. This year, about 974 birds fledged our nestboxes, which is 145 more than last year! 476 of this year’s birds were tree swallows, and 385 were western bluebirds. We also had 83 house wrens, 25 ash-throated flycatchers, and 5 white-breasted nuthatches that fledged from the boxes.

All but the nuthatches had greater fledging success this year than in 2019. Western bluebirds had the greatest overall increase in number of fledglings: last year there were 196, and this year we had 385! As usual, tree swallows dominated the western portion of Putah Creek while western bluebirds thrived most in the middle and eastern end. Ash-throated flycatchers and house wrens did best in the middle portion.

The Davis Nestbox Network along the Covell Greenbelt finished its second year with new boxes on poles on the north end and much overall success. 15 out of the 20 boxes had at least one egg in them, and the boxes produced 85 fledglings in total (tree swallows and bluebirds).

*Soon I’ll update with our Bird Haven highlights from further north. There were several ash-throated flycatcher nests up there this year!

Walking trail at our Picnic Grounds site in Davis

Lastly, I hope everyone is staying safe this summer. My thoughts go out to those affected by the recent fires throughout California.


July and Season Ending

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!

Tree swallow looking out of a large nestbox made for ducks. Photo by Monica Burnett.

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.

Tree swallow adult with aluminum USGS band visible on its leg. Photo by Dr. Kevin Keel.

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.

Western bluebird nestling in hand, about to be banded. Photo by Hanika Cook.
Tree swallow nestling being held on its banding day. Photo by Hanika Cook.
Putah Creek surrounded by green vegetation at Interdam near Lake Berryessa. Photo by Hanika Cook.



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.

Western bluebird fledgling near the UC Davis Arboretum where it had hatched less than two months ago. Photo by Mary K. Hanson.
Another angle of this fledgling. The visible color bands allow us to look in our records and find where this bird came from and how old it is. Photo 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!

Ash-throated flycatcher eggs near Dry Creek in Winters. Photo by Hanika Cook


Summer banding

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!

Ash-throated flycatcher nestling banded at Bird Haven, from the first box banded of this species up there this season. Photo by Danielle Fradet
Small tree swallow nestling in Winters opening its wings. Photo by Hanika Cook
tree swallow nestling in someone's hand
Older tree swallow nestling in Winters, just banded. Photo by Hanika Cook
Nestbox monitors Michelle Mah (left) and Estefania Maravillas (right) banding western bluebirds at Russell Ranch. Photo by Michelle Mah
Bluebird nestling with new bands in Winters. Photo by Hanika Cook