FEMALE PENDULINE TITS (REMIZ PENDULINUS) CHOOSING HIGH-QUALITY NESTS BENEFIT BY DECREASED INCUBATION EFFORT AND INCREASED HATCHING SUCCESS

Female penduline tits preferably choose males with relatively bigger n ests. Nest size is a reliable indicator of thermal nest insulation cap acity and hence nest quality. In this study we investigate possible be nefits for females choosing larger nests. Possible benefits of choosin g well insulated nests could be a) increased time-off the eggs, i.e., more time for food gathering and activities for self maintenance, and b) increased hatching success due to maintenance of a stable thermal e nvironment. Field observations and results from aviary experiments rev ealed that females adjust their attentive period according to ambient temperature, whereby time-off increases with higher ambient temperatur e. Data corrected for ambient temperature and clutch size demonstrated that lime-off during incubation is positively correlated with nest si ze. However, body condition of incubating females did not increase wit h time-off Despite increased time-off hatching success is higher in la rger nests. Thus, female mate choice for larger nest size may evolve f rom decreased incubation requirements with no loss in hatching success .