Artificial nest box use by the North Island saddleback: Effects of nest box design and mite infestations on nest site selection and reproductive success

Abstract

The importance of artificial nest boxes for North Island saddlebacks (Philesturnus carunculatus rufusater) on Tiritiri Matangi Island has increased significantly, suggesting that “natural” nesting cavities are now a limited resource for this growing population. The design and position of artificial nest boxes directly affects the likelihood of saddleback use for nesting: small boxes (0.005 and 0.0lm3) with large (140–160 mm high) north facing openings had the highest probability of being used. One of the disadvantages of using artificial nest boxes in conservation management is the potential for parasite build‐up. Two species of mesostigmatid mites were found in the artificial nest boxes used by saddlebacks on Tiritiri Matangi Island. One was an undescribed species of Dermanyssid mite the other was Ornithonyssus bursa, the fowl mite. The numbers of mites detected increased over the saddleback nesting cycle from September to December. However, our results strongly suggest that, for saddlebacks, no negative correlations exist between mite abundance and chick weight, fledging date, or the number of fledglings produced. Mite abundance was extremely variable and did not correlate with nest box temperature or relative humidity.