ROOSTING PREFERENCES OF NORTH ISLAND BROWN KIWIS (APTERYX MANTELLI)

摘要

The North Island Brown Kiwi (Apteryx mantelli) is a nocturnal endangered species endemic to New Zealand. The protection of suitable habitat is key to the species' recovery; however, little is known about their habitat requirements. We studied the diurnal roosting behaviours of kiwis by intensely tracking 41 radio-tagged, non-breeding adults from May 2010 to February 2012 on Ponui Island, New Zealand. From these birds, we collected 3,997 roosting locations in three different macro-habitat types (scrub, forest, and swamp) and described 223 roosting burrows in the forest macro-habitat. Overall, we discovered that kiwis were roosting generalists; three quarters of the study population was found in more than one macro-habitat and just 5% used only a single type of micro-habitat. However, using compositional analyses, we found that they did show some clear preferences. On a macro-habitat level, kiwis preferred forest habitat over scrub or swamp. Furthermore, on a micro-habitat level, they preferred roosting inside trees, either living or dead, and holes in the ground over roosting in decomposing vegetation or holes associated with creeks. The least preferred micro-habitat type consisted of overhangs produced by ground slips. Kiwis were most likely to use long burrows with small entrances that were oriented downhill. Our findings suggest that priority should be given to protecting mixed landscapes with large, mature, dynamic native forests.