Research Projects – Colony Farm

VARC’s bird monitoring and banding program is conducted at our Colony Farm field station in Coquitlam. It records the age, sex, wing and tail lengths, fat deposits, and body mass of captured species, as well as studying molt patterns in birds. The data gathered is useful in many areas of avian research, including migration, behavioral research, and longevity, as well as differences between age and sex groups, life cycles, weight and plumage changes, population monitoring and habitat use. Bird banding also helps us understand how to conserve the land and environments in which these species live and breed.

Migration Monitoring

Migration monitoring during April – May and August – October allows us to determine the significance of the habitat at Colony Farm as a stopover site for migratory birds. Many of the birds we band have large fat loads either initially or on their stopovers here which typically last for a few days to as much as a week or more. The caloric density of large fat deposits is enough to sustain the energy demands of small migrant songbirds making non-stop migratory flights of some 700 kms or more and this is just one of several such flights they must make to take them from their Central American winter grounds to their Canadian nesting grounds. Banding data allows us to prove the significance of the habitats these birds are using as refueling sites on their stopovers here.

Bird Surveys

In conjunction with the bird banding study in Colony Farm Regional Park, VARC also conducts a weekly bird survey which commences on April 1 to coincide with the start of Spring migration and concludes October 31 corresponding with the end of Fall migration. Surveys have been conducted since 2009, the first year banding occurred in the park.

The survey transect has been established along a set route encompassing the Wilson Farm North banding station as well as a broader area of the park. Bird presence/absence as well as general abundance detected during these surveys can correlate closely to those birds captured at the banding station.  However, it also gives us a broader picture of avian species present in Colony Farm Regional Park.

Indicators of Bird Breeding Activity

During the breeding season (June – July) all birds captured are examined for breeding characteristics to determine which species breed in the park and their preferred nesting habitat.

Breeding passerine birds develop breeding characteristics which help us to separate males from females in sexually monomorphic species which otherwise look exactly alike.

Many species are sexually dimorphic meaning we can sex the bird based on characteristics such as plumage coloration and/or size. But in sexually monomorphic species both males and females look identical and these species can only be sexed in the hand in spring and summer when they show these breeding characteristics i.e. a cloacal protuberance (CP) or a brood patch (BP).

In many monomorphic species, the male’s cloaca becomes enlarged and bulbous during the breeding season, the base narrow and tip swollen, the purpose being to store sperm and aid with copulation. This is called a cloacal protuberance. Female passerines on the other hand conduct most if not all of the incubation and develop brood patches (BP). At this time they will lose the feathers on the breast and belly to facilitate direct skin contact and maximum heat transfer to the eggs for incubation.

Radio Frequency Identification – Tree Swallows

Radio frequency identification (RFID) allows the unique identification of individuals and automated recording of the presence of tagged birds at fixed locations such as nest boxes.

RFID is a means of contact-free electromagnetic communication between a reader and a transponder. In this application, a passive integrated transponder (PIT) tag weighing less than 0.004% of the bird’s body mass is attached to the bird and transmits a unique identification number to a reading device with an RFID circuit board and antenna. Every time a bird with a PIT tag comes near the RFID reader, the bird’s identity is recorded along with the date and time of the visit. The resulting data can provide incredibly detailed information about the behaviours of the tagged birds.

Tree swallows are familiar birds in coastal British Columbia, but their abundance has declined in the last 40 years due to unknown causes. Since they readily accept nest boxes, Tree Swallows represent an ideal candidate species for the use of RFID technology. The main objective of this project is to develop RFID capability to study the nesting behaviour of tree swallows in the park. The technology is being used to better understand the connections between adult nesting behaviour, and weather, food availability and nestling growth and survival.
This research is using innovative technology to address important ecological and conservation questions, while fostering new external collaborations and providing students with a significant experiential learning opportunities.

Click here to see our research paper published in North American Bird Bander

Investigating pesticide residues in Hummingbirds

VARC has recently become involved in scientific research into the accumulation of neonicotinoids and other insecticides in hummingbirds and honey bees.

This research is being carried out by several groups, including Environment and Climate Change Canada (Dr. Christine Bishop), Bees Actually (Julia Common) and the Hummingbird Project of British Columbia (Dr. Alison Moran).

Neonicotinoids, such as imidacloprid, are among the most widely used insecticides in the world, but there is accumulating evidence that some breakdown products are toxic to some animals, such as insects, and they have been linked to Colony Collapse Disorder of honey bees and other adverse ecological effects. Neonicotinoids are routinely sprayed on agricultural crops, such as blueberry fields found throughout the Fraser Valley of British Columbia. These insecticides can then be picked up by animals feeding on the pollen and nectar from the blueberry flowers. This research is comparing insecticide levels in the cloacal fluids of hummingbirds (Anna’s and Rufous) and honeybee nectar and water in hives near to sprayed fields and at control sites away from sprayed fields.

VARC’s contribution to this research is the collection of hummingbird cloacal fluid at its main banding site at Colony Farm Regional Park and at a site in Tsawwassen, Delta, B.C. Collection occurs once a week, with hummingbirds caught in a specially designed trapped. The hummingbirds are banded, biometric data taken and cloacal fluids collected, very carefully. The hummingbirds are not harmed during this process and fluid collection is non-invasive. All samples are stored on ice and sent to ECCC for analysis.

Swainson’s thrush (Catharus ustulatus) – Molt-Migration Research(Click here for more information)

The term molt-migration is given to individuals that leave their breeding grounds and head south to find a suitable location to undergo their annual prebasic molt before continuing southward migration. Unlike other species which molt either on their summer grounds or on their winter grounds, Swainson’s thrushes overlap their molt with migration. Birds may continue to migrate while actively molting or they may initiate and/or complete their molt in an area south of their breeding grounds.

Where arid conditions on the breeding grounds in late summer are not especially conducive to molting, adults routinely migrate substantial distances to special molting areas. In general, their movement away from increasingly drought-stricken breeding habitats is timed for their arrival somewhere in the desert Southwest U.S. or Mexico during the period of monsoon rains.  The flush of insects associated with these rains constitutes a bumper-crop resource for the energy and protein-demanding molt process.

Research on adult Swainson’s thrushes at Colony Farm shows that some adult birds caught for banding after the breeding season are in the early stages of their adult prebasic molt suggesting the old field habitat could be a special molting area for this species.

Post-breeding Monitoring of Juvenile Birds

During the post-breeding season (August – October) capture rates of hatch year (HY) birds increase dramatically. By monitoring the numbers of adults and juveniles caught for banding we can better understand population growth and dynamics.

The combination of diverse, structurally complex plant communities and the presence of resources – food, water and shelter with high aquatic insect productivity in spring and high insect/fruit production in fall – that are typically present in the Park, provide a high-quality environment for migrant birds. 

Age structure for birds captured for banding shows that there are more sub-adults than adults (53.1%/46.9%) during spring migration and that sub-adults make up 90.4% of the total birds banded during fall migration. This is consistent with the age structure of captured birds during our years of monitoring, further supporting the importance of habitat at the Park for dispersing juveniles especially in the fall. Most birds (+/-90%) caught for banding during this period are hatch year (HY) birds born during the current calendar year.