Fall Wildlife

Now that we’ve finished bat and mammal monitoring for now, Putah Creek field work is done for the season. We got our last 2021 bat recordings and mammal photos in the beginning of October — here are a few of those photos!

Mule deer

Raccoon tails
Striped skunk
Western gray squirrel
Desert cottontail rabbit

The rain is finally coming to the area, hopefully bringing some relief to the vegetation and wildlife along the creek. Meanwhile, we’ll be working on sorting through data and preparing to gather more next spring!


2021 Nesting Season Summary

Putah Creek in Winters

We’ve been typing up and organizing this year’s nest box data, and now we have some preliminary summary info! This year, our Putah Creek nest boxes produced about 742 fledglings. About 368 of these chicks were tree swallows, and 304 were western bluebirds. We also had 36 ash-throated flycatchers, 23 house wrens, and 11 white-breasted nuthatches that fledged.

Ash-throated flycatchers had more successful nests on our trails than usual this year, with about 44% more fledglings in 2021 than in 2020. White-breasted nuthatches, although uncommon as always in our boxes, had more than twice as many fledglings this year compared to last year. Tree swallows and western bluebirds each had a slight decrease in number of fledglings this year, and house wrens this year produced less than a third of the number of last year’s fledglings. However, the success rate of each egg for all species (from laying to hatching and fledging) was very similar to last year’s success rates. House sparrows (a European species that harms native birds) tried to nest in several boxes in Winters, but we were able to remove all of their nests before they made much progress.

The Davis Nestbox Network along the Covell Greenbelt also had many healthy chicks again this year. 74 chicks fledged: 59 western bluebirds and 15 tree swallows. A couple of new nest box trails were monitored in the north Davis area and in Woodland too!

Bird Haven had three species in their nest boxes: house wrens, ash-throated flycatchers, and tree swallows. House wrens dominated as usual for that site, with about 178 fledglings. The flycatchers had about 10 fledglings while the single tree swallow nest produced 4 fledglings (marking the first time our Bird Haven boxes have produced tree swallow fledglings!).

In addition to organizing this kind of nest summary data, we’re still monitoring the creek for bats and mammals for a little longer this year, and we’re sorting through the associated audio and photo data. Obtaining info straight from the field is just the first step! There is a lot of processing, proofing, vetting, and other steps to go through before we have our results, but it’s exciting to see what Putah Creek can tell us about its many wildlife inhabitants!

Raccoon tracks in dirt near the creek


Second wave of nestlings, and cleaning up

We’ve been doing a lot of banding these past couple of weeks during the second, smaller wave of nestlings in the boxes. There are a few more chicks to band this week, but most boxes have been inactive for some time, so our Putah Creek field leaders have started cleaning them out. The Bird Haven crew has finished their field season, and the Davis Nestbox Network crew is just about done too. They’ve all done a great job keeping up with all of the nest box monitoring and banding this year!

Volunteer intern Alyssa bringing down a nest box in the Arboretum to check the nest
Field coordinator Alex checking a nest at the Arboretum
Field coordinators Rosie and Alice comparing wing colors of a male (left) and a female (right) western bluebird chick while banding and taking measurements
Tree swallow chick with a new band

Our bat and mammal monitoring season will go on a bit longer. This month our trail cameras got photos of an American mink, another first for our cameras this year! Raccoons, opossums, and various squirrels continue to visit our camera bait stations the most.

American mink caught on trail camera in Winters, not far from Stebbins Cold Canyon
Opossum with baby on top (bottom left of the photo), from a trail camera in Winters
California ground squirrel, near Russell Ranch
Raccoon trying to get to bait, near the Putah Creek Sinks east of Davis

I’ll soon be indoors more, organizing this year’s nest and banding data to make summaries of their success, numbers, and any patterns. I’ll share that here later on!

View of Winters Putah Creek Park from the north side while banding a box of tree swallows


Putah Creek Species

So far at all of our Putah Creek sites this year, there have been over a hundred western bluebird nests with at least one egg, and slightly more tree swallow nests with at least one egg. House wrens have made five nests, mostly at one site near Lake Solano in Winters. Ash-throated flycatchers have made 12 nests, which is pretty high for our nest boxes!

Western bluebird eggs, in a feathery nest taken over from tree swallows
Tree swallow nestling on banding day
Ash-throated flycatcher chick with new bands
Ash-throated flycatcher eggs in their fur nest

We’ve been able to catch a few adult birds this year. It’s interesting to see where they’re from if they’re banded, and if they’re not, we give them a band and maybe take some quick measurements.

Adult tree swallow with metal band

Our Putah Creek mammal cameras have captured a nice variety and number of animals in June, including a bobcat, cute deer and skunks, opossums, and many others! A few birds often make it into the photos too.

Young striped skunk
Deer fawn
Hungry opossum

I hope everyone has a nice three-day weekend – stay safe out there!

Sunset near Putah Creek at Mace Blvd, Davis


First wave of nestlings

There were a lot of nestlings hatching around the same time through May and the beginning of June, but our field team pulled together and banded the first and biggest wave of nestlings this season! So far we’ve banded around 180 chicks, including all five of our usual species: western bluebirds, tree swallows, house wrens, ash-throated flycatchers, and white-breasted nuthatches.

Ash-throated flycatcher chick
House wren chick with new bands
Western bluebird chick with new bands
Tree swallow chick squatting in its nest

Our field leaders this year are (from left to right below) Alice, Rosie, and Alex. They’ve been doing a great job checking on nest boxes, measuring and banding birds, and organizing data. Big thanks to them for all their work!

Now there’s a bit of a lull for us while we let older chicks fledge and while new eggs are being laid. Next month will likely bring a lot of new chicks and second nest attempts, and maybe more of the late-nesting ash-throated flycatchers.

Small tree swallow chicks, not long after hatching

This week we’ll have some extreme heat for several days in a row, and the drought in general affects these birds’ ability to find insects to feed their chicks. I hope we all get less extreme weather in the weeks ahead.

Tree swallow adult at its nest box, checking on its chicks after I banded them


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.