Maritime Swallow Research

From the 1970s to the 2000s, the four species of swallows found in Canada’s Maritime provinces — bank, cliff, tree and barn swallows — have suffered serious declines. In the case of bank swallows, populations have plummeted an astounding 98 per cent. Find out more about these species.

Wildlife Preservation Canada funded research by former Canada’s New Noah Tara Imlay to identify the causes for swallow declines in the Maritimes. The two main culprits being investigated are changes in the availability of the insects that swallows feed on and threats on migration routes and wintering grounds. Tara and her team have set up nest boxes for tree swallows and established a nest monitoring and banding program for all four species across sites in New Brunswick and Nova Scotia. This enables the researchers to closely monitor breeding success and survival and relate it to information on food availability. Meanwhile, geolocators are being used to track the birds’ behaviour and migration routes. In addition, blood and feather samples are collected from returning birds. These samples are analyzed to identify wintering areas and provide insights into wintering ground conditions and their impact on return rates and reproductive success.

From 2013 to 2016 Tara and her team monitored 1,248 swallow nests at dozens of sites in New Brunswick and Nova Scotia, checking for timing and success of breeding. The team banded 2,303 nesting and juvenile swallows and retrieved 14 geolocators from returning birds for analysis at Dalhousie University. Forty-four adult bank swallows were tagged with radio-transmitters to determine foraging and roosting habitat use. Preliminary results suggests that three of the four swallow species have begun breeding earlier than usual in recent years. Pairs that breed later in the season face a shortage of insects during nestling development that can negatively impact young birds.

The data collected in this project will help us to understand why steep declines in swallow populations are occurring, giving us the information we need to plan conservation efforts for these species. It also has broad implications for the conservation and recovery of other aerial insectivores across North America.

Imlay, T.L., Angelier, F., Hobson, K.A., Mastromonaco, G., Saldanha, S., Leonard, M.L. (2019). Multiple intrinsic markers identify carry-over effects from wintering to breeding sites for three Nearctic-Neotropical migrant swallows. The Auk: Ornithological Advances, manuscript # AUK-S-19-00201-1, accepted.

Imlay, T.L., Nickerson, D., Horn, A.G. (2018). Temperature and breeding success for cliff swallows Petrochelidon pyrrhonotanesting on man-made structures: ecological traps? Canadian Journal of Zoology, doi: 10.1139/cjz-2018-0224.

Imlay, T.L., Hobson, K.A., Roberto-Charron, A., Leonard M.L. (2018). Winter locations, migratory connectivity and fidelity of three declining Nearctic-Neotropical migrant swallows. Animal Migration 5: 1-16.

Imlay, T.L., Mills Flemming, J., Saldanha, S., Wheelwright, N., Leonard, M.L. (2018). Breeding phenology and performance for four swallows over 57 years: relationships with temperature and precipitation. Ecosphere 9:e02166. 

Imlay, T.L., Mann, H.A.R., Leonard, M.L. (2017). No effect of insect abundance on nestling survival and mass in Barn, Cliff and Tree Swallows.  Avian Conservation and Ecology 12: 19.

Imlay, T.L., Steenweg, R.J., Garcia-Perez, B., Hobson, K.A., Rohwer S. (2017). Temporal and spatial patterns of flight and body feather molt for Bank, Barn and Cliff Swallows. Journal of Field Ornithology 88: 405-415. (read only page https://t.co/aU1sSVe1Yu )

Tara Imlay’s work with Wildlife Preservation Canada began in 2008, when she was contracted to study the behaviour and movements of eastern loggerhead shrikesreleased from our conservation breedingprogram. The following year, she became our 20th Canada’s New Noah and conducted research on kestrel productivity and breeding success during her time in Mauritius. Her experience with birds continued in 2010 and 2011, when Virginia Tech hired her to document the potential impacts of the Deepwater Horizon oil spill on overwintering populations of piping plovers. In 2011, Tara returned to work for Wildlife Preservation Canada as a species recovery biologist, coordinating the Eastern Loggerhead Shrike Recovery Program.
Today, Tara is a PhD candidate with Dalhousie University, conducting field research into the causes of rapid population declines of swallows in the Maritimes. Tara holds a Bachelor of Science degree in Zoology from the University of Guelph and a Master of Science in Biology from Acadia University.

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