Inter‐annual variation in the breeding chronology of arctic shorebirds: effects of weather, snow melt and predators

• Published in: Journal of Avian Biology
• Main Authors: Smith, Paul A., Gilchrist, H. Grant, Forbes, Mark R., Martin, Jean‐Louis, Allard, Karel
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2010
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Arctic
• Online Access: http://dx.doi.org/10.1111/j.1600-048x.2009.04815.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-048X.2009.04815.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-048X.2009.04815.x

Arctic breeding shorebirds travel thousands of kilometres between their wintering and breeding grounds, yet the period over which they arrive and begin to initiate nests spans only several weeks. We investigated the role of local conditions such as weather, snow cover and predator abundance on the timing of arrival and breeding for shorebirds at four sites in the eastern Canadian arctic. Over 11 years, we monitored the arrival of 12 species and found 821 nests. Weather was highly variable over the course of this study, and the date of 50% snow cover varied by up to three weeks between years. In contrast, timing of arrival varied by one week or less at our sites, and was not well predicted by local conditions such as temperature, wind or snow melt. Timing of breeding was related to the date of 50% snow melt, with later snow melt resulting in delayed breeding. Higher predator abundance resulted in earlier nesting than would be predicted by snow cover alone. We hypothesise that when predation risk is high, the value of potential re‐nesting exceeds the energetic risks of early breeding. Synchrony of breeding was significantly higher in late breeding years suggesting a relatively fixed date for the termination of nest initiation, after which nesting is no longer profitable.