Environmental heterogeneity decreases reproductive success via effects on foraging behaviour

Environmental heterogeneity shapesthe uneven distributionof resources available to foragers, and is ubiquitous in nature. Optimal foraging theorypredicts that an animal's ability to exploit resource patches is key to foragingsuccess. However, the potential fitness costs and benefits of foragingin a heterogeneousenvironment are difficult to measure empirically. Heterogeneitymay provide higher-quality foragingopportunities, or alternatively could increase the cost of resource acquisition because of reduced patch density or increased competition. Here, we study the influence of physical environmental heterogeneityon behaviour and reproductive successof black-legged kittiwakes, Rissa tridactyla. From GPS tracking data at 15 colonies throughout their British and Irish range, we found that environments that were physically more heterogeneouswere associated with longer trip duration, more time spent foragingwhile away from the colony, increased overlap of foragingareas between individuals and lower ...