The quality of pied flycatcher (Ficedula hypoleuca) and great tit (Parus major) females in an air pollution gradient

Great Tit (Parus major) Science Article 5

abstract

We studied whether pied flycatcher (Ficedula hypoleuca) and great tit (Parus major) females differed in quality between polluted and unpolluted habitats. Comparing female condition between incubation and nestling periods, we aimed at testing whether biometric differences in F. hypoleuca females were caused by assortative settlement (i.e. intraspecific competition) or as a consequence of breeding in environments exposed to different levels of pollution stress. Body mass, wing length, fat reserves, age distribution, timing of breeding and breeding density of females were measured along an air pollution gradient from a copper smelter in SW Finland in 1991-1994. We found few differences in female quality which could be explained by assortative settling. Females were of the same size in all areas. At nestling time P. major females were heaviest in a moderately polluted area. However, females in the most polluted area were not lighter than those in background areas. Female fat reserves in both species were smaller in the polluted area in one cold breeding season. This suggests that natural (weather) and human induced (pollution) stress factors affected female condition additively. The proportion of young F. hypoleuca females was slightly higher in the polluted area than elsewhere. P. major females started laying earlier near the factory complex than farther away. F. hypoleuca females laid later in the polluted area in early breeding seasons but in late seasons laying started simultaneously everywhere. Especially F. hypoleuca bred more sparsely in the polluted area. Observed differences in the condition of F. hypoleuca females along the pollution gradient emerged mainly in the course of breeding.

Eeva, T., Lehikoinen, E. & Sunell, C. 1997, Ann. Zool. Fennici 34: 61-71

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