We’ve got breeding birds!- March 26, 2022 Banding Cycle

Above: Greenery by one of the nets (we’ll see how long it lasts)

Start at 7:00am, closing at 12:00pm
Total 19 nets up
Total 37 birds, 15 species

• 1 Mourning Dove (Zenaida macroura)
• 2 Anna’s hummingbird (Calypte anna)
• 5 Allen’s hummingbirds (Selasphorus sasin)
• 1 Unknown Hummingbird (escaped, either Allen’s or Rufous)
• 3 House Finches (Haemorhous mexicanus)
• 7 Gambel’s White-crowned Sparrows (Zonotrichia leucophrys gambelii)
• 2 Golden-crowned Sparrows (Zonotrichia atricapilla)
• 3 Song Sparrows (Melospiza melodia)
• 1 Lincoln Sparrow (Melospiza lincolnii)
• 2 Spotted Towhees (Pipilo maculatus)
• 2 California Towhee (Melozone crissalis)
• 1 Audubon’s Warbler (Setophaga coronata auduboni)
• 1 Common Yellowthroat (Geothlypis trichas)
• 1 California Thrasher (Toxostoma redivivum)
• 2 Bushtits (Psaltriparus minimus)
• 3 Hermit Thrushes (Catharus guttatus)

So, it’s been a while since I did a blog post on banding. Truth is, the last two cycles was stressful for me. My dad and I were switching off nets with everyone else, weaving all throughout the canyon checking for birds, having to remember the exact location of each net amongst the tall vegetation. Despite having few birds to process, I was struggling with removing birds from the nets, a seemingly unique puzzle for each individual. Sometimes the birds can get really stuck— with the fine net crossing over the bird’s shoulders, getting wrapped around the neck, or the whole body becoming completely twisted.
Removing the birds is ideally a swift and easy enough process so as not to stress the bird out. But what happens when you yourself get stressed and you feel like you’ve tried everything to untie the bird? (No birds were harmed.) You look at the bird’s face and wish that they could just be free from the net. This was me last cycle, but it wasn’t me this cycle. No one said being a bird bander was a breeze.

The morning started off foggy. I cautiously climbed a Western Sycamore tree that had fallen not far from the banding station a few weeks ago. Not wanting to get hurt before even starting the job, I jumped down from the trunk. Excited to start the day once the master bander showed up in his van.

We unloaded the van and got to work. My dad and I took the four nets closest to the station: 1, 11, 12, and 26. My dad and I had the helpful experience of setting up three different nets further up the canyon last cycle, but it was good to be back at the nets we had trained on for months.

By the time of the first net round, we had already caught a bird: a Mourning Dove. Mourning Doves are a little trickier than most. Not being a Passerine (an order of birds adapted to gripping branches), they seem to just lay in the net, making them able to escape rather easily with a strong beat of their wings. Knowing this, I was cautious. Soon enough, I had removed my first Mourning Dove from a net!
The after second year (ASY) male was gorgeous, and luckily well behaved. Even after taking the measurements, the dove had decided to stay in my palms a little longer as I lay my hand flat for him to fly off. It was a tender moment.

By the next net round 45 minutes later, I was bringing back lots of birds (and taking them out rather quickly by my own standards). The three nets I checked yielded four birds: two Golden-crowned Sparrows (one a recapture!), an Allen’s Hummingbird, and an Anna’s Hummingbird. Golden-crowns are a migratory species from the fall, so it was nice to see them before they fly off north in the coming week or so. Coming back to the station with four bags in hand, of course I unknowingly kept the hardest bird in my opinion: the Allen’s Hummingbird.

Golden-crowned Sparrows are easy, you can quickly tell age by the color of the crown and sex can’t even be determined. The Anna’s Hummingbird was obviously an adult male with his stunning iridescent pink head and gorget. But the Allen’s Hummingbird was different. Since Rufous Hummingbirds are beginning to show up for the spring, I first had to double check that this hummingbird was in fact an Allen’s. Looking at the r2 (second tail feather from middle), I searched for a slightly notched feather, which would be indicative of a Rufous. No notch: cool, Allen’s. Next, aging and sexing the bird. The gorget was not much help. I was stuck between three options but eventually went with after hatching year (AHY) female after guidance from the master bander.

Other banders were getting some cool birds too! The Gambel’s White-crowned Sparrows that were caught were beginning to molt into their adult plumage. Their once fully brown crown indicating an immature bird fading into a bold black. Very fashionable indeed.

As I processed yet another Allen’s Hummingbird a net round later, I noticed one of the banders had a California Thrasher! If you’ve read by posts before, you’ll known thrashers are one of my favorite birds! After the bird was processed and people got their photos, I got ready to get photos of my own. Only… the bird escaped. Luckily one of the banders was able to share with me her photos!

Spring is here and we have to start looking for indications of breeding. Brood patches (BP) occur in females and the males of some species depending on nesting behavior. Because a bird’s feathers naturally keep them warm, by shedding their belly feathers, the bird is able to provide direct contact from the underlying blood vessels to their eggs or young.

A cloacal protuberance (CP) can only be found in males. Cloacal protuberances are essentially bulbous masses where male birds will produce and store their sperm for the breeding season. The presence of a cloacal protuberance indicates a reproductively active adult male bird.

As such, the presence of a cloacal protuberance or brood patch can be a great indicator for the age and sex of a bird in most cases. To expose the CP/BP, we gently blow air to the location. Though I didn’t get much practice last year distinguishing CP/BP (because not many birds were breeding due to the drought), I’m eager to learn this year.
Below, I circled the cloacal protuberances of two adult male birds.

As migratory birds such as Audubon’s Warblers (only 1 caught this cycle versus 10 exactly one month ago) and White-crowned Sparrows migrate north, the Zuma Canyon banding station looks forward to spring migrants such as Rufous Hummingbirds, a variety of warblers and flycatchers, and many more.