Reproductive success and productivity of the Cyprus Wheatear Oenanthe cypriaca, a migratory, island endemic

Abstract

Population dynamics of annually breeding bird species depend crucially on productivity, and so this variation can help us understand the causes of declines in migrant birds. We investigated variation in annual productivity 2010–2012 in the Cyprus Wheatear Oenanthe cypriaca, a small endemic migrant passerine at the National Forest Park (NFP) of Troodos. Clutch size for first nests was usually five, although 0.40 eggs lower in 2011. Nest survival did not vary with year, nesting attempt, or clutch initiation date, but was significantly higher in the chick (0.96; 0.88–0.98, 95 % CI) versus the egg stage (0.74; 0.62–0.83, 95 % CI). The number of chicks fledged from a successful nest varied with nest type—with first nests and second nests after failure being similar producing ~3–4.5 chicks dependent on year, and with second nests after success producing ~2 chicks, independent of year. There were only weak positive or negative effects of clutch initiation date dependent on year, controlling for nest type, and no effects of male age on productivity. After fledging, chicks had a >95 % chance of surviving the first month, but with a greater probability of one or rarely two chicks per brood dying if fledged later in the season. Renesting rate was significantly different in all years (26, 48, and 78 % renesting): 2010 had a much lower renesting rate after success with very few second broods (29 versus 76 % and 73 % in 2011 and 2012, respectively). Overall productivity per territory did not vary with year with 3.96 ± 0.09 SE chicks alive 1 month after fledging. Cyprus Wheatears showed several unusual breeding parameters including a highly variable renesting probability, high nestling, and very high fledgling survival, resulting in exceptionally high productivity. This may be because renesting is constrained by high mid-summer temperatures and low abundance of chick predators.