Of catbirds, chats, and challenges

We are excited to welcome Kristen Mancuso to the blog today! Kristen is a PhD candidate at the University of British Columbia Okanagan studying songbird migration ecology and physiology. For more about Kristen, see the end of this post. 

As I wrap up my PhD at the University of British Columbia Okanagan, I think back fondly on 4 summers of field work across North America. In collaboration with other organizations, I did fieldwork in northern California, western Montana, and Mexico…but most of my time was spent in the south Okanagan Valley.

One of my study sites in the South Okanagan Wildlife Management Area. The wild rose sure smells nice but walking through it is very scratchy.

The Okanagan Valley is a hot tourist destination in the summers, known for its lakes, beaches, wineries, and fruit. For biologists, it’s also known for its unique biodiversity – the semi-arid desert habitat is home to species occurring nowhere else in Canada.

My PhD research aims to learn more about the full annual cycle of 2 species of songbird: the yellow-breasted chat and the gray catbird. The population of yellow-breasted chats in the south Okanagan Valley is listed as Endangered federally, with only a few hundred breeding pairs in the province. In contrast, the gray catbird is abundant and not of conservation concern. Studying the two species together allows for a comparison between a common and an at-risk riparian songbird species. Environment and Climate Change Canada has been monitoring both species in the region for many years, and this PhD project piggybacks on their efforts.

Both yellow-breasted chats and gray catbirds are migratory, spending most of the year south of the Canadian border. In North America, most research on migratory songbirds occurs on the breeding grounds, but a better understanding of their migration and overwintering life stages is crucial to identify and address potential threats. This is especially important for endangered species, such as the yellow-breasted chat, to aid recovery efforts.

However, it wasn’t until very recently that tracking technology became small enough to use on songbirds. Now, we have lightweight GPS tracking devices, weighing only 1 gram, that birds can carry with them on migration. This is the technology I used to track chats and catbirds across their full annual cycle. But in order to follow the path of a migrating bird, we needed to capture birds and attach the GPS tags, then recapture them a year later to remove the tags and download the data. Therefore, most of my time in the field was spent capturing, resighting, and recapturing birds.

Bird capture

To capture birds, we used mist-nets. Mist nets are a common tool to capture songbirds and are made of a very fine, soft mesh that is nearly impossible to see. The net is stretched between two poles and contains multiple pockets. When a bird flies into the net, it falls into a pocket and gets tangled but is not harmed. We gave each bird we caught a combination of 3 unique colour bands and a standard numbered band.  The colour bands allowed us to identify the individual from afar. A subset of birds were also given a harness with a GPS tag attached, which they carried like a backpack.

Chats are territorial and will respond to playback of other chats’ songs, so we targeted specific territorial males with strategically placed nets, using a stuffed dead chat as a decoy. Catbirds don’t appear to be as aggressively territorial as chats and unfortunately, don’t consistently respond to playback, so our best bet was to passively capture them first thing in the morning. This meant getting up at ungodly hours. I had my schedule down to the minute: wake up at 2:30 AM, leave by 3:00 AM, arrive at site by 3:20 AM, and then set up ~ 8 mist-nets by headlamp as fast as possible so they were ready to catch birds before first light, around 4 AM.

My field technicians carrying banding gear from a chat territory.  The white styrofoam box contains the decoy.

My main catbird site along a trail. A mist net is barely visible on the left.

A catbird given some fresh colour bands. Two black bands on its left leg, plus a green and standard band on its right leg.

GPS tags attached to the back of yellow-breasted chat.

GPS tags attached to the back of colour-banded gray catbird.

Resighting colour banded birds

The purpose of resighting colour-banded birds was to identify individuals that needed to be recaptured to remove GPS tags and also to monitor the return rates and survival of birds. Survival estimates are valuable for conservation and monitoring efforts to better understand if birds are making it through the winter and migration and returning to breed.

To resight birds, we used binoculars and high-zoom cameras, which sounds easier than it is. Yellow-breasted chats and catbirds live in places no sane person would normally venture into: dense bushes of wild roses and thickets of poison ivy. In order to protect ourselves, we wore thick rain gear. Did I mention that the south Okanagan is also known for its intense sun and heat? Temperatures in excess of 30°C are not uncommon, and the rain gear quickly turned into a sweat trap. To add to the challenge, the clouds of mosquitoes (and to a lesser extent, ticks) meant we also often wore bug nets to cover our faces.

Both chats and catbirds are relatively sneaky and hard to see, but males periodically pop up out of the dense vegetation to sing and defend their territory. This often meant a long, hot wait for the bird to appear – and when it finally did, we typically only had a few seconds to get a photo. All too often, our attempts ended in failure. Sometimes we heard the bird but couldn’t see it; other times, we saw the bird with our eyes but couldn’t find it with the camera. Often we were too slow, and the bird went back into thicket before we could snap the picture. And in the most frustrating cases, we got the photo – only to find that it wasn’t usable for identification purposes for a multitude of reasons: the camera focused something other than the bird, the photo was over- or underexposed, the bird’s legs (and therefore colour bands) were hidden…

The chat is front and centre and yet my camera focuses on the tree in the background.

Catbird silhouette. Not helpful for ID.

Nice shots of chat but can’t see legs.

Nice shots of catbird but can’t see legs.

Even when we did get a clear photo, interpreting the colour of the bands wasn’t always easy. Standard aluminum bands can appear white or light blue. Red bands can fade and look like orange.

But the challenge was in part what made it so appealing! When we finally nailed a bird’s colour band combination, there was a definite sense of accomplishment. Looking up who the bird was, when and where it was banded, and whether it was seen the previous year – in short, its whole history – was exciting. The oldest catbird in our study was at least 6 years old, and the oldest chat at least 11!

Despite the sleep deprivation, poison ivy rashes, and rose scratches, spending the summers studying these birds was something I looked forward to every year. Being outside watching the birds at dawn in their natural habitats, foraging, singing, and building nests, was beautiful and peaceful. Using new technology to learn more about their migration was fascinating. Having great field technicians was an added bonus, and being able to go swimming or go for ice cream after a long day in the field made the summers unforgettable.

Kristen Mancuso is a PhD candidate at the University of British Columbia Okanagan studying songbird migration ecology and physiology. Her PhD project is in partnership with Environment and Climate Change Canada. She has a love for fieldwork and exploring the great outdoors. After her PhD, Kristen hopes to continue her career in wildlife conservation. This fall she will be working as a bird bander for Mackenzie Nature Observatory. Follow her research on Instagram @yellowbreastedchatresearch