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Sex Differences in Preening Behaviour in the White Stork Ciconia ciconia

Zolnierowicz K. M., Nyklova-Ondrova M., Tobolka M.

Polish Journal of Ecology

2016

Vol. 64, nr 3

431--435

Preening is a type of feather maintenance behaviour in birds, that fulfils an important role in grooming. Preening may also be important for signalling quality of mates. Therefore we hypothesized that the frequency of preening may be related to sex and population density of White Stork Ciconia ciconia. We observed preening activity of 25 pairs in Western Poland at the beginning of incubation, when preening frequency is the highest. Birds were observed on the nest, because most preening behaviour occurs there. We found that being on the nest males spent proportionally more time on preening than females (on average 30% vs. 16%). Females spent more time preening when their mate was present at the nest. There was no significant relationship between preening frequency and indirect quality indicators (arrival date, laying date, hatching date, clutch size, brood size) nor between the distance to nearest neighbours and the time males and females spent on preening.

Importance of juvenile mortality in birds' population: early postfledging mortality and causes of death in White storks Ciconia ciconia

Tobolka M.

Polish Journal of Ecology

2014

Vol. 62, nr 4

807--813

Early post-fledging mortality of White Stork during the period from the first flight to their autumn departure from natal area was described. Data from eight breeding seasons (2005−2012) about 56 cases of death of juvenile White Storks from a study area in Western Poland were collected. For a comparison the data of 55 cases of death from recoveries data deposited in Polish Bird Ringing Centre from entire Poland were included in analysis. Early post-fledgling mortality rate varied from 2 to 11% (mean 4.3%) of all fledglings per year. The main causes of death were collision with power lines and electrocution which in Western Poland constituted 60% and in entire Poland − 78% of death cases with known causes. Other anthropogenic causes constituted responsibly 25 and 13% and natural causes − 15 and 9%. Mean distance where dead storks were found was 183.3m from natal nests, while 73% were found closer than 100 m from their nests.