The reproductive biology of the Syrian Woodpecker Dendrocopos syriacus in a newly colonized area of south-eastern Poland

Abstract

In 2003–2006, 73 Syrian Woodpecker nests were studied in a 305-km2 area of the agricultural landscape in SE Poland. The median egg-laying date was found to be 12 May and the median fledging date was 20 June (the earliest laying date was April 24 and the latest fledging date was July 25). Females laid from two to seven eggs (median 5.0 eggs, n = 56). An average of 4.4 young hatched per nest (SD = 1.18, median 5, maximum 6, n = 41) after 9–13 days of incubation (median 10 days, n = 37). Two to six nestlings left successful nests (median 4, n = 37) after 24–30 days (median 27, n = 36), with a mean of 2.8 (SD = 2.24, median 3, n = 56) young fledging per nest. The main reason for the loss of young observed in 31 % of the Syrian Woodpecker broods was nest parasitism by starlings. These results suggest that the process and dynamics of the range expansion of the Syrian Woodpecker are influenced by a higher reproductive output of Syrian Woodpeckers at the extremities of its range as compared to that of the rest of the Syrian Woodpecker population.