Prospecting Birds, and First Nest!

The tree swallows and bluebirds have begun to prospect and claim boxes, and I saw our first nest of the season! This was at our site in Winters that we had not been able to monitor for a few years, so it’s exciting to see these new boxes already being used. A tree swallow was seen peering inside, and it was already banded, so it was probably one that we had banded nearby in previous years. Hopefully I can get a closer look and a precise ID of that bird later on.


One of our new boxes in the Davis Nestbox Network has a couple of feathers and a little grass inside too! A tree swallow was seen prospecting another box there as well. I’m glad they’re beginning to find their way to these nesting options.


The flooding is subsiding slowly, leaving a lot of muddy areas for mammals and wading birds to leave a variety tracks.


We’ve still been hard at work getting boxes ready. The birds will be laying eggs before we know it!


Estefania Maravillas, one of our field leaders, checking a nestbox


Flooding, Flowers, and Fixing Boxes


A nestbox still hanging just above the flooded creek

A few days ago, the other field leaders and I started cleaning and checking the boxes in preparation for spring. It’s been raining a lot for the past couple of weeks, and the Lake Berryessa glory hole is spilling over. Many of our nestbox sites are flooded, and the rain and wind will limit the days we can go out, but we’ll still get some maintenance done before we start our weekly monitoring.

Flowers are blooming plentifully on the trees along the trail at Picnic Grounds. The vegetation is making use of the abundant water.

Each year there is always some wear and tear to the boxes by the time we start checking them again. Some of our nestboxes will need repairs or replacement, like this one that had its entrance pecked out all the way to the top. The boxes make a nice place for some critters to hide or sleep in during the winter,  so we’ll be scraping out wasp nests, evicting rats, and shaking out old bird poop. There are most likely some boxes that have been washed away by the high creek, but we’ll have to wait and find out after those areas are no longer submerged.

Some bluebirds have been hanging around the Arboretum nestboxes. It will be exciting to see the first nests being built soon!



Big Plans for New Nestboxes

Winter is coming to an end in a few weeks, and spring is on its way. Nestbox monitoring season is about to begin!

My name is Hanika Cook, and I am the new nestbox project coordinator at the Museum of Wildlife and Fish Biology. I started as an intern and then one of the field leaders for this project when I was a student, and now I’ll be coordinating all of the teams. While Evelien’s shoes are hard to fill after the amazing work she’s done, I’m excited to take on the challenge and start the field season.

New boxes in Davis Nestbox Network! Photos courtesy of Alison Ke. (Click to enlarge)

This year, we’ll also be adding on two new nestbox sites outside of Putah Creek. Bird Haven up in Glenn County will be monitored by Estefania Maravillas and her team, and the Davis Nestbox Network along the Covell greenbelt of Davis will be led by Alison Ke. Many new boxes have been put up in preparation for the breeding season. It will be interesting to see what kinds of birds use the boxes in these two very different areas. While birds may not take to new boxes at first, I have my fingers crossed that the new sites will have plenty of nests this year. This year we’re celebrating 20 years of the Putah Creek Nestbox Highway Project, so it seems fitting that it’s expanding.

I’ll be continuing this blog, so stay tuned for this year’s nestling news!


Hanika Cook with a White-breasted Nuthatch, 2017


Evelien’s final nestboxing

This is my final post here, as my position at the museum as the nestbox project coordinator is coming to an end. The project will continue, but this is the last few days of my experience with the Putah Creek Nestbox Highway. I was thinking about waiting until my last day to post this, but time is running short and I did not want to forget.

The field season is not over just yet, but I’ll be leaving California in less than two weeks. I’ll start with some updates and notes about this season and then end the post on a personal note.

All of our remaining active boxes are Western Bluebirds. I think because of their varied diet, they are able to nest successfully so late in the season. So far this season has produced 860 fledglings total and there are still a few more to come. Although it is not the final fledgling count, this is already the most number of fledglings this nestbox program has produced in a single year.


Western Bluebird nestlings

Kristen and I were surprised to find a new clutch of bluebird eggs recently, in a box that was otherwise inactive for the whole season. What we thought were the last two bluebird broods will be banded next weekend, but it seems like I’ll miss the new final clutch of bluebirds.


Kristen Z. and Evelien D. with western bluebird nestlings

Recaptures and re-sights are my favorite part of the nestbox experience. It tells us part of the birds’ stories and teaches us about their movements along the creek.


Western Bluebird male

Catching adult birds is challenging with the pole lifter device, but it is so rewarding. When we catch a banded adult, the first thing I do is look up the band information. Sometimes I don’t even wait until I’m back in my office and I’ll end up squinting at my phone to look at a tiny screen of spreadsheets with all the band numbers, trying to see where and when the bird was originally banded.

One of the highlights of this season was finding multiple 7-year old Tree Swallows. One was banded as a nestling in an orchard in 2011, and she raised a brood this year at Russell Ranch. Another was banded as a second-year bird in 2012 and has been seen nesting at Picnic Grounds multiple times (2012, 2016, & 2018). I think it’s amazing what these birds are capable of and how long some can live. The other extraordinary recurring bird is the bluebird, Tufty (I posted in April), who has nested at the same box every year since 2014. His nest of eggs was depredated in April this year and he has not been seen nesting again since. Although his nesting efforts ended on a sad note, he has been very faithful to his overall very successful box. He has a special place in my heart because every year I’ve been a part of this project he has not failed to show up for me.

Each year the breeding season zips by and it’s sometimes hard for me to believe I’ve been a part of the nestbox program for 5 seasons now. I feel like we just got our first eggs yesterday. I will miss Davis tremendously, which has been my longest home of 7 years, and I will miss the museum family that has been so wonderful to me. I’m going to start graduate school in Manitoba, Canada, in September. I’m extremely excited for this new adventure because I’ll be studying Purple Martins and their migration!

This photo I took in 2014 (below) is still my favorite of all of my nestbox photos. Like the nestlings getting ready to leave the nest, it is time for me to fledge from Davis and start the next chapter in my life.


Goodbye everyone, and thank you for following this blog. As the Putah Creek nestbox project continues, so will this blog but it will be lead by someone else. I’ve enjoyed sharing updates about the nesting birds and the creek, and I hope you have all enjoyed reading it as well.

-Evelien de Greef


Final nesting


Western Bluebird

The nestbox season is winding down. The last box of House Wrens were banded yesterday and the last Tree Swallow and Ash-throated Flycatcher chicks are coming up soon.


Bluebird eggs

There are a good amount of Western Bluebirds still active, in fact we even got new bluebird eggs this week! The photo to the left is a new clutch found at Picnic Grounds this morning. Yesterday a new clutch was found at Old Davis Rd. We’ll continue to look our for any more new ones, but those two may be the last nests.

This isn’t the final count, but so far 700 nestlings have fledged. There are still a handful more boxes left to band next week, and just a few more that have yet to hatch.

Also an update on the bluebird swallow mixed nest mentioned in the previous post- the tree swallow egg disappeared (possibly depredated, or thrown out by the bluebird), and there are now just bluebird chicks in that nest.

The breeding season is coming close to the end, and so is my stay in Davis. Time is going by so fast I can hardly believe it’s already middle of July.

-Evelien de Greef

Bluebird and swallow combined nest

Here’s an interesting case where a Western Bluebird took over a Tree Swallow nest. Last week this nest had 1 swallow egg, and today a bluebird has taken over with 5 more eggs and is now incubating all of them. This behavior of taking over a nest with eggs is seen more often in Ash-throated Flycatchers, but any bird has the ability to do it. Perhaps the Tree Swallow egg was abandoned and the bluebirds thought it was time for their turn, or perhaps the bluebird did decide to take over an occupied nest.


Western Bluebird nest (5 eggs) with +1 Tree Swallow egg

Nest take-overs are very common in the nest building stage (seen by the layers of different nesting material) but not as common when there are already eggs present. This is the first time I’ve seen a bluebird nest incubating an additional swallow egg. I do not expect the Tree Swallow egg to hatch, but we will see what happens in a couple weeks!

We have banded our 2nd clutch of Ash-throated Flycatchers, and we just got a couple more new flycatcher nests!


Ash-throated Flycatcher nestlings

We are still getting more and more hatches every week. Here is a Western Bluebird chick just about 7 days old.


Western Bluebird chick ~ 1 week old

It’s always great to see very attentive parents. This House Wren went right back to her chicks after I checked her nest.


House Wren

And here’s a Western Bluebird mother keeping watch.


Western Bluebird on nest box

So far 560 nestlings have fledged. Lots of boxes are starting on their second round!

-Evelien de Greef

Robert Walsh Exit Seminar

Tomorrow is Bobby Walsh’s exit seminar at UC Davis in Academic Surge room 1375 at 10:30am. He is an expert birder researcher and has been a large part of the nestbox project. We are very lucky and very excited to see his exit seminar. Congratulations to Bobby for completing his PhD! Please come by to see his talk tomorrow!