Chickadees in the Garden
Compiled by: Diane Bell
In September 2019 at our fall FOG Meeting Jan Wijmenga gave a presentation on Chickadee research at the University of Alberta Botanic Gardens. In 2017 Jan, his wife (K. J. Mathot) and a small group started studying Chickadee foraging behaviour in the Botanic Gardens. Their project runs mainly in the fall and winter studying the behaviour of individual chickadees in their winter flocks, focussing on individual differences in behaviours related to feeding. Feeders were installed throughout the Botanic Garden to monitor the chickadees throughout winter.
An update on their research can be found below.
Chickadees in the Garden
In the summer of 2017 we initiated what we hope will be a long-term research project investigating causes and consequences of individual differences in black-capped chickadees (Poecile atricapillus) at the University of Alberta Botanic Garden.
The University of Alberta Botanic Garden not only features beautiful indoor show houses, extensive cultivated gardens and plant collections, but also an additional 75 hectares of natural area. This mixed forest area is very suitable for black-capped chickadees and a few weeks after first installing feeders at 16 evenly spaced locations, all of them were being used by chickadees. We currently use eight feeder locations, to better suit our experimental setup.
Individually Marked Chickadees
Every fall and winter, when the chickadees are grouped in their winter flocks. We try to catch and band as many individuals as possible. Each chickadee we catch gets a metal band with a unique number, issued by the Canadian Bird Banding Office. Besides that, it gets a unique combination of three colour bands. These colour bands allow us to identify individuals without the need to re-capture them.
In the first fall/winter season of 2017-2018 we caught and marked close to 200 individuals. We will continue to catch and mark chickadees every fall/winter season, to maintain a close to fully marked population. By the fall of 2019 we had banded just over 500 chickadees.
With an estimated 150-250 black-capped chickadees in the study area in the fall/winter season, we have a great study system which allows us to ask questions about among-individual differences in foraging behaviour, for example: How do chickadees invest in learning about the distribution of food? Which individuals search for food, and which simply follow? How do individuals respond to predator cues? Ultimately, we are interested in understanding how and why individuals make different decisions, and whether this type of variation matters (i.e., has consequences for survival and/or reproduction).
Survival and Flock Characteristics
Throughout the fall and winter season, we spend time getting re-sightings of marked individuals, either by using binoculars or by setting up a video camera at the feeders. This gives us information on the survival of individual chickadees and we can find out which feeders each individual chickadee uses and how much individuals stick to the same flock throughout the fall and winter season.
Automatic Feeder Visit Registration
Even for experienced band readers, it can be challenging to get read the combination of colour bands properly, as chickadees tend to be very active. On top of that, one observer can only be at one feeder at the time and typically focus on only one individual at the time.
To get more detailed information on individual feeder use, we also equip chickadees with a Passive Integrated Transponder (PIT) tag. These small tags are embedded in one of the colour bands and each provides a unique Radio Frequency Identification (RFID) code when near an antenna, just like a key-fob used to access a building. Our first trials, with our original feeders, taught us that the squirrels and white-tailed deer emptied the feeder’s too fast, prevented chickadees from feeding and destroyed both the feeders and the antennas. On top of that, the circuit boards proved to be very unreliable.
A red squirrel inside one of the feeders. Photo by Jan Wijmenga.
We ordered a new RFID system and designed and built new, deer- and squirrel proof feeders, which we installed in the fall of 2018. Within weeks we had close to a hundred chickadees regularly using the feeders. With individual visiting rates averaging about 70 a day, we now register up to 250,000 visits per month in the fall and winter season!
Wildbird General Store
Having hundreds of thousands of feeder visits every month, we go through a lot of black oil sunflower seeds. Thank you to Edmonton’s Wildbird General Store for generously providing us with the seeds at a discounted rate.
Having this reliable monitoring system in place enabled us to begin to address our questions by collecting both baseline- as well as experimental data. In the winter of 2018-2019, MSc Student Josue Arteaga Torres ran an experiment looking at how black-capped chickadees value different modalities of information about predation danger. This led to the first publication based on this field research:
Arteaga-Torres, J. D., J.J. Wijmenga, and K.J. Mathot. 2020. Visual cues of predation risk outweigh acoustic cues: a field experiment in black-capped chickadees. Proceedings of the Royal Society B: Biological Sciences 287, 20202002
In the subsequent winter of 2019-2020, MSc student Elène Haave Audet looked at how individual black-capped chickadees use social and personal information to make foraging decisions. This data is currently being analysed.
Due to COVID-19, there will not be any experiments running in the current winter, but collection of valuable baseline data will still occur.