caa a22 4500 463175026 CHVBK 20180406164823.0 cr unu---uuuuu 170326e20070101xx s 000 0 eng 10.1007/s10336-006-0106-0 doi (NATIONALLICENCE)springer-10.1007/s10336-006-0106-0 Manipulation of laying effort reveals habitat-specific variation in egg production constraints in Great Tits ( Parus major ) [Elektronische Daten] [Raivo Mänd, Vallo Tilgar, Priit Kilgas, Marko Mägi] It has been suggested that a bird's clutch size is not limited by the amount of resources available at the time of laying but that differences in the availability of food for nestlings is the ultimate underlying factor determining spatio-temporal variations in clutch size. However, habitat-related variations in egg production ability has yet to be investigated explicitly. We studied the breeding of Great Tits Parus major in deciduous and coniferous forests in the same area. The sizes of both the clutches and the eggs were, on average, larger in the former habitat than in the latter. A number of females were induced to lay more eggs than usual by removing four eggs from designated experimental clutches early in the laying period. These manipulated females laid approximately one egg more than control females, with the number of additional eggs laid not differing between the habitats. However, in both study years the relative size of the extra eggs - relative to the mean size of earlier laid eggs of the same clutch - was smaller in the coniferous habitat than in the deciduous habitat, while there was no habitat-related difference in the relative size of the last-laid eggs of control clutches. This result indicates that some form of proximate limitation during egg-laying period can contribute to the relatively small clutches and eggs in the coniferous habitat. Our results emphasize the need to take egg production costs into account when attempting to account for spatial variation in the reproductive behaviour of birds. Dt. Ornithologen-Gesellschaft e.V., 2006 Breeding constraints nationallicence Clutch size nationallicence Egg production nationallicence Habitat variation nationallicence Parus major nationallicence Mänd Raivo Institute of Zoology and Hydrobiology, Centre of Basic and Applied Ecology, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia aut Tilgar Vallo Institute of Zoology and Hydrobiology, Centre of Basic and Applied Ecology, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia aut Kilgas Priit Institute of Zoology and Hydrobiology, Centre of Basic and Applied Ecology, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia aut Mägi Marko Institute of Zoology and Hydrobiology, Centre of Basic and Applied Ecology, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia aut Journal of Ornithology Springer-Verlag 148/1(2007-01-01), 91-97 0021-8375 148:1<91 2007 148 10336 https://doi.org/10.1007/s10336-006-0106-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10336-006-0106-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mänd Raivo Institute of Zoology and Hydrobiology, Centre of Basic and Applied Ecology, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia aut NATIONALLICENCE 700 1- Tilgar Vallo Institute of Zoology and Hydrobiology, Centre of Basic and Applied Ecology, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia aut NATIONALLICENCE 700 1- Kilgas Priit Institute of Zoology and Hydrobiology, Centre of Basic and Applied Ecology, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia aut NATIONALLICENCE 700 1- Mägi Marko Institute of Zoology and Hydrobiology, Centre of Basic and Applied Ecology, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia aut NATIONALLICENCE 773 0- Journal of Ornithology Springer-Verlag 148/1(2007-01-01), 91-97 0021-8375 148:1<91 2007 148 10336 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer