A Departure, and a Museum Celebration!

Hello all, Hanika here! My time at UC Davis is coming to a close: this is my last week as the Putah Creek Biologist for the Museum of Wildlife and Fish Biology. The blog and our projects will continue though of course! It has been a great learning experience, and I’ve really enjoyed working with the many amazing students and other folks that have helped or collaborated on projects over the last four years. I’ll of course miss spending time with the songbirds too. This week I had my two last avian transect surveys, and it’s a lovely time to see fall birds along the creek. A great way to say goodbye to field work here.

Light mist over the grass in the morning near Old Davis Road. Photo: Hanika Cook

On another note, next week is the Museum of Wildlife and Fish Biology’s 50th Anniversary celebration! The event will take place on October 13th from 5:30 pm to 7:30 pm. For more info and to register (must be before Oct. 11th!), click here: https://registration.ucdavis.edu/Item/Details/869

Have a wonderful Fall!

All the best,

Hanika Cook

Myself after a fall bird survey. Photo: Hanika Cook

Bat Monitoring Season Closes

Hello all!

With the return of crisp, cool mornings and changing leaves comes the end of bat monitoring season. Bat activity is at its peak during the summer months, and the last month for monitoring for this season was September. Over the course of the season, we were able to collect data about the different bat species who frequented areas around Davis and Winters. There are thirteen species in all that have been detected on Putah Creek, including the few species covered in earlier posts.

Mammal activity at these sites stayed consistent. In the last couple weeks of monitoring, we caught some coyote on camera after many months of seeing evidence of their activity along the creek. The river otters eluded our cameras, however, did consistently use a latrine of their own making at one of our sites. Raccoons, opossums, and deer were fairly common visitors as well. In all, a successful season for the Putah Creek Bat and Mammal Monitoring Project!

A coyote caught running by a trail cam. (MWFB)

Two raccoons try (unsuccessfully) to make off with the bait can. (MWFB)

A deer peers cautiously from the brush. (MWFB)

Until next season!

Stay batty, Angie

Putah Creek Bat and Mammal Monitoring August Updates

In August we saw lots of activity on the creek, including a bobcat!

Blurry bobcat. (Photo: MWFB)

Deer activity has been high as well, with many of the mamas foraging with their babies in the early afternoon hours. We have seen them active along the creek where orchard access is available. Orchards are prime foraging spots for deer as their preferred food like tender grasses, leaves, and shrubs are plentiful in these areas.

Mama and baby caught on a trail cam. (Photo: MWFB)

A couple bat species you may see around Davis are the Mexican free-tailed bat (Tadarida brasiliensis) and Yuma myotis (Myotis yumanensis).  Mexican free-tailed bats live in large colonies, one of the most notable in the area residing underneath the Yolo bypass. You can see them fly in and out of their roosts around dusk and dawn. They love to forage on moths and flying ants among other insects (yolobasin.org). Their migration to their wintering sites extending down into Mexico will begin soon. Yuma myotis are not migratory instead hibernating in the winter months. They prefer to hunt near water, feeding on aquatic insects like mayflies (norcalbats.org). Bat species like these provide invaluable ecosystem services like pest control, and their continued monitoring is so important.

Mexican free-tailed bat (Tadarida barsiliensis). Photo credit: USFWS/ Ann Froschauer https://commons.wikimedia.org/wiki/File:Mexican_free-tailed_bat_(8006850175).jpg
Yuma myotis (Myotis yumanensis). Photo Credit: Daniel Neal https://commons.wikimedia.org/wiki/File:Myotis_yumanensis_(Yuma_myotis)_(11362476624).jpg

Stay batty!


2022 Quick Summary

Now that nest box field work is done for the year, it’s time to organize and summarize this past season’s nest monitoring data. About 918 chicks fledged from the Putah Creek Nestbox Highway in 2022, which is almost 100 more than last year! There were about 1400 eggs and 1080 chicks in total. 481 of the fledglings were Tree Swallows, 368 were Western Bluebirds, 38 were Ash-throated Flycatchers, 21 were House Wrens, 5 were White-breasted Nuthatches, and 5 more were Oak Titmice. House Sparrows attempted to nest several times in a few boxes at Winters Putah Creek Park, but all their nests were successfully removed before they had chicks.

Compared to last year, there was a slight increase in the number of Ash-throated Flycatcher fledglings and a slight decrease in House Wren fledglings. Tree Swallow and Western Bluebird fledgling numbers both increased. As usual White-breasted Nuthatches had just a few chicks on the Putah Creek Nestbox Highway – one successful nest this year, two last year. Lastly, this year’s Oak Titmouse nest was pretty special, as we had not had any known Oak Titmouse eggs in our nest boxes, let alone fledglings, since 2010!

Our bat and other mammal monitoring season will end at the end of this month, and then later we can summarize the species we observed for that project this year too. Soon we’ll share some more of those photos. Meanwhile, I hope everyone is hanging in there while we wait for this long heat wave to end!

Cacti thriving in the heat in the UC Davis Arboretum. Photo: Hanika Cook


The Real Last Chicks of the Year

We had one more late bluebird nest on Putah Creek with healthy chicks! They hatched in a nest box near Mace Boulevard in Davis under a shady oak tree, and I banded them recently. Next week I’ll check to see if they all fledged.

Western Bluebird chicks at about 7 days old, a week before banding. Photo: Hanika Cook
Bluebird nestling with new bands at about 14 days old. Photo: Hanika Cook

Banding seems to have concluded recently along the Davis Covell Greenbelt too, a couple of days after the final Putah Creek brood. Another season of many healthy chicks!

Bat and other mammal monitoring continues on Putah Creek, and fall avian surveys are just around the corner.


Bird Adaptations

Modern birds descended from dinosaurs. I find that looking at nestlings always does a good job of reminding me of the avian lineage. Along the way, birds have evolved some unique adaptations.

Closeup of Western Bluebird ear. Photo: Jenna Turpin

Let’s start our tour of the bird body with their ears. Normally their ear is covered by feathers and many people assume they have none. While the nestling is still growing its feathers, we can easily see they do in fact have ears, just not externally. They do have a fully functioning internal ear that senses sound through the hole you can see on nestlings, or by moving the feathers of adult birds.

Western Bluebird uropygial gland, Photo: Jenna Turpin

The next stop on the tour is another part not easily seen on adult birds. The small bump just above the base of the tail feathers is called the uropygial gland. It secrets oil that the bird uses for preening. During preening, the bird applies oil to each feather using its bill. This process maintains and waterproofs the feathers.

Western Bluebird nestling toes gripping my finger. Photo: Jenna Turpin

Western Bluebird nestlings quickly learn how to grip on to nearby objects because they are a perching species. Bird species have varying toe plans depending on the primary function of their feet. Hawks have strong talons for gripping prey. Herons have long toes for walking on top of the mud. Ducks have webbed feet for efficiently paddling in the water. Bluebirds have thin toes with three toes facing forward and one rear-facing for perching easily.

I hope this inspired you to take a closer look and think about why birds look the way they do! Happy exploring!


Nestlings vs. Fledglings

Hi, I’m Jenna, one of the field leaders for the Putah Creek Nestbox Highway this year. As the nesting season comes to an end for our birds, the last chicks will be fledging the nest. Fledge is the period of time between leaving the nest and being a full adult. A fledgling’s body is entirely covered in feathers, giving it the ability to fly. However, it still needs time to learn how to fly well enough to care for itself. So during the fledgling phase, the fledgling stays in the area of the nest it hatched from and continues to receive care from its parents.

A fledgling has made fast progress. Just around three weeks ago it was an almost entirely bare, pink nestling the size of a thumb. Now it has its first set of feathers. As a juvenile, the fledgling still has different feathers than a full adult. Their color is more dull. For example, in Tree Swallows fledglings do not yet have their full blue-green iridescence and instead look more brownish.

Just hatched Western Bluebird nestlings with soon-to-hatch eggs in the nest. Photo: Jenna Turpin

If you see a healthy fledgling on the ground, it is important to remember not to remove it from the area. It needs time to learn how to fly and its parents are seldom far away.

If you see a nestling (a chick that is not fully feathered) on the ground, it may be time to step in. You can try gently placing it back in its nest if you are able to reach it. Don’t worry, touching a chick will not cause its parents to abandon it, that is a myth! You can also reach out to your local wildlife rehabilitator for help.

A fledgling Tree Swallow (left) sitting on a branch near its parent (right). Photo: Jenna Turpin

Thank you for caring about the birds and doing your best for them!


Last Putah Creek Banding This Year

It’s been a very hot couple of weeks, but our last nest box chicks have been doing pretty well. We’ve still been busy banding the last couple of weeks and I’ve seen mostly lively, healthy nestlings. The nesting season is just about over though, and today I believe we’ve banded the last Putah Creek nest box chicks of 2022! They were bluebirds in one of our Old Davis Road nest boxes. Outside of the Putah Creek area, there may still be a few chicks to band in north Davis along the Davis Nestbox Network in the coming weeks, but our creek team only has a few nests left to check before we store equipment till next year. These nests just need to be checked to see if the birds fledged after we banded them and left them in peace for a couple of weeks. I can’t thank our field leaders Alice, Jenna, and Vicky enough for checking each site through the end of the season.

Last bluebird chicks banded on Putah Creek this year, in their nest box near Old Davis Rd. Edit: this fuzzy nest was built by an Ash-throated Flycatcher but taken over by Western Bluebirds! Photo: Hanika Cook
Tree swallow parent at a pole-mounted box by Winters Putah Creek Park. Photo: Hanika Cook
Tree swallow chick showing off its growing wings. Photo: Hanika Cook
Tree swallow nestling peeking out (left), then being fed by a parent (right), taken through binoculars. Photo: Hanika Cook
Ash-throated flycatcher chicks in their fur nest. Photo: Hanika Cook

The next step is to type up and report all of the bands to the USGS Bird Banding Lab so if these birds are seen by others, they can report them to the lab and connect with us to exchange info on the birds. Soon I’ll also summarize the numbers and species of birds in the nest boxes this year to share here!

For now, stay cool!


Bats and Other Mammals Along Putah Creek

Spot the deer in this picture taken along Putah Creek!

Hi, I am Angie, and I monitor bats on Putah Creek! Putah Creek is an incredible place to view an abundance of wildlife all year-long. The spring and summer months are the best time to monitor mammal activity along the creek. Bats are of particular interest as they provide natural pesticide services to the agricultural areas the creek runs through. The Museum of Wildlife and Fish Biology at UC Davis created a project monitoring bat acoustics at key points along the creek. Bats use hedgerows and water features like rivers and creeks to help them navigate and forage. Therefore, it is beneficial to set up the monitoring equipment along the creek, as we expect many of the species will frequent those areas during their night flights. Poles fit with microphones are suspended over the creek to record bat activity. In these areas we also set up camera traps to monitor other animals that may travel along the creek. Among those we’ve observed this season are river otters, deer, and opossum!

Opossum caught on trail camera. (MWFB)

Over the next few months, we will introduce you to some of the species we monitor along the creek, today we will start with the Pallid Bat.

Antrozous pallidus. Photo by Connor Long. (https://commons.wikimedia.org/wiki/File:Pallid_Bat_(Antrozous_pallidus).jpg)

The type of pallid bat found along Putah Creek, Antrozous pallidus,eats a variety of insects including beetles, moths, crickets, and arachnids such as spiders and scorpions. They prefer dry, open land near rocky outcrops to roost during the hot days. They forage relatively close to their roost, only traveling at most within a few miles away. They will forage insects directly from the ground, flying approximately 2-8 feet above. This makes open, agricultural areas like those found in Davis a prime location for them!

Stay batty,


July Updates on the Creek

Hi, I’m Alice, one of the field coordinators for the Putah Creek Nestbox Program. It’s a beautiful week to be on the creek! The heat is subsiding, at least for a little bit, so now is the time to spend the afternoon with a book. It’ll definitely get hot again soon, after which it’ll be a good time to float down the creek in an inner tube.

The songbirds on Putah Creek are finishing off their second/third attempts, but some eager parents are even getting started on their third attempts now! It’s been a pretty productive season for all the sites. I got lucky enough at one of my own sites (Russell Ranch) to get two White-breasted Nuthatch nests, but they were sadly both depredated before the chicks hatched. At the same site, however, we had six Ash-throated Flycatcher nests!

Quite strangely, I’ve been finding a lot of dead nestlings and even some dead adults this season, especially in Winters Park. It’s no coincidence that this is also the only site where I get House Sparrows attempting to nest in the nestboxes 😦 These invasive birds likely went into the boxes and killed the adult Tree Swallows. That’s why it’s important for us to quickly identify and remove any House Sparrow nests we see in the nestboxes. The nestlings probably died from heat stress or being smothered by their nestmates, but one has to wonder why this is happening so much in Winters Park in particular.

It’s always sad when baby birds don’t make it before they fledge, but more often than not it doesn’t happen. Most fledglings are successful, and some even come back to the nestboxes to parent their own young. It’s always interesting to wonder what happened, as we are only given a few pieces of this amazing ecology puzzle.

Hope you get to spend some time outside!