Post-mortem examinations of New Zealand birds. 2. Long-tailed cuckoos (Eudynamys taitensis, Aves: Cuculinae)*

ABSTRACTLittle is known about the biology of long-tailed cuckoos(Eudynamys taitensis). In this study, 79 dead cuckoos, mostly from the wider Auckland region, New Zealand, were examined and dissected to shed light on the sex ratio, morphology, breeding season and diet. There were no statistically significant sexual differences in the means for weight or body measurements. However, immature birds had significantly shorter bill, wing and tail lengths than adults. In adults, gonads were enlarged (for breeding) from October to January, while all cuckoosidentified (from plumage) as immatures had small gonads. Of 888 food items identified from 62 gizzards, 94% were insects. The main foods were cicadas and shield-bugs ( Hemiptera, 48% of food items), stick-insects ( Phasmatodea, 19%) and wētāsand katydids ( Orthoptera, 13%). Small vertebrates (lizards and birds’ eggsand nestlings) were a minor dietary element (1% of food items; 13% of stomachs). Cicadas, stick-insects and praying mantids (large insects abundant ...