Egg-cellent nests

Right now we have 21 nests with eggs! More and more are coming each week. Currently we have 3 (!!!) complete White-breasted Nuthatch nests all incubating. The nuthatch nests are a great treat to have in our boxes since we don’t get those very often. For the rest of the egg-filled nests we have 6 House Wren nests, 5 Western Bluebird nests, 7 Tree Swallow nests.

We have nine field teams of UC Davis students checking boxes every week. They’ve been a big help and have also been very enthusiastic, making this project especially fun. 🙂


Kimberly C., Lisa P., and David E. checking a nestbox


Kevin H., Yenifer G., and Maria F. checking a nestbox

The creek has been quite active! Other spring breeders and migrants are arriving, like flycatchers, warblers, vireos, and orioles. Some of the wintering birds are still remaining, such as the white and golden-crowned sparrows, they’ll be leaving soon.


Putah Creek at Picnic Grounds

Many of the birds like to poke their heads out of their nestbox to keep watchful eye. If you ever walk through the UC Davis Riparian Reserve, you might see some do this! It’s a great spot for birding too and it has a lovely trail.


Tree Swallow at nestbox

-Evelien de Greef




Nuthatch Incubator

Although I just posted a blog entry yesterday, I couldn’t help myself to put another one up today because I wanted to update that we have 2 nests in incubation (both White-breasted Nuthatch)! One Nuthatch nest at Russell Ranch, and one at Mace Blvd. At Mace Blvd this morning when we took this box off the branch, the female White-breasted Nuthatch quickly poked her head out of the hole but then went straight back to guarding her eggs. Here she is sitting tightly on her nest. After snapping a quick photo we put the box with her back up. We’ll have to wait until next week and try to check the box when she’s on her break so we can count how many eggs there are.

WBNU in nest

White-breasted Nuthatch sitting on her eggs

Boxes are filling in quickly, there’ll be hardly any empty boxes soon. Here’s one of the teams checking boxes this morning:


Annie M., Danielle M., and Faith Y. checking a nestbox

Here’s a Tree Swallow with some grass in the mouth. If you look closely, you can see there is a band on one of the legs!


Tree Swallow with some nesting material

-Evelien de Greef

First Tree Swallow clutch!

Here we have our first Tree Swallow eggs for this season! In addition, we have found some House Wren eggs as well. It’s crazy how in just a few weeks activity in the boxes is going to be very very busy.


Tree Swallow nest and eggs


House Wren nest

Some House Wrens like to build their nest all the way to the top of the box, as a way to prevent competitors and predators from getting in (photo left). While it works quite well, it is not 100% effective. In one of the House Wren nest this morning (a tall one), I reached in to feel for any lining or eggs, and instead I touched a rat, thinking, “wow this is a lot of lining in the nest,” then realized it was fur. Luckily the rat didn’t move or bite, and I had to bang the side of the box to get the rat to jump out and leave. Normally rats just leave as soon as you open the box door, so that was the first time for me that I accidentally pet a rat.




Color banded bluebird

We have yet to see some bluebird eggs, but they are coming soon. There are quite a few nests ready to go. Also, here is likely the same female Western Bluebird I saw on December 10th, 2017 (Black over Blue on her right leg, and Green over Silver on her left). She’s at the same spot I saw her in December, and now the box she’s using has a nest ready for her eggs.



The notorious Tufty has his nest built his nest and is waiting for his lady to lay her eggs. We had a nice view of his legs this morning. Going strong at 5 breeding seasons!


Tufty, the Western Bluebird

-Evelien de Greef

House Sparrow nests

While we welcome a variety of species in our nestboxes, we don’t allow House Sparrows to nest in them. House Sparrows are originally from Europe and are considered an invasive species here in the states, meaning they are non-native and harmful to the ecosystem. They add to the competition for cavities and can perform aggressive takeovers, so we remove any House Sparrow nests we find. They are quite persistent sometimes, this box had a nest we removed 1 week ago, and this morning another nest again:


House Sparrow nest

House Sparrows like to make a dome/cave shape and fill up the entire box (seen above). Three years ago there were 10 House Sparrow nesting attempts overall on the nestbox highway, it dwindled down to 2 the year after, and 1 last year. If the pattern continues, we shouldn’t see too many of these in our boxes this year.


Opal, the House Sparrow

Since they are invasive and unprotected birds, I took in two chicks found in a nest box 3 years ago. A recent photo of one of them is on the right. Since they have a special place in my heart I am probably biased, but I have seen their sweet side from their naps, kisses, nibbles, and singing.

-Evelien de Greef


Easter Sunday Special

On this Easter Sunday, we have the 1st egg of the nestbox highway for this 2018 season – a White-breasted Nuthatch egg. This egg was laid this morning at Russell Ranch. In fact, right now we have 3 White-breasted Nuthatch nests overall (all at different sites)!


White-breasted Nuthatch nest and egg

While there are still many empty boxes, there are also some bluebird, house wren, and tree swallow nests ready for eggs. Stay tuned!

-Evelien de Greef