Call survey method for monitoring endangered North Island weka ( Gallirallus australis greyi )Submitted by osnz-admin on Tue, 03/15/2011 - 22:44
|Title||Call survey method for monitoring endangered North Island weka ( Gallirallus australis greyi )|
|Publication Type||Journal Article|
|Year of Publication||2000|
|Authors||Bramley, GM, Veltman, CJ|
|Type of Article||paper|
|Keywords||call counts, census, detection, Gallirallus australis, rails, Weka|
We investigated the use of call count surveys to monitor weka numbers for management purposes. A Generalised Linear Model based on data from 11 1 nights of listening for weka at Rakauroa (North Island, New Zealand) showed that the number of calls recorded was influenced by listening site and month, but not by wind direction, wind strength, cloud cover, phase of the moon, rainfall or temperature. Mean number of calls heard was highest between December and March, with a peak in January. More birds were heard from certain listening sites. Although there was no correlation between any of the environmental variables and weka calling, wind, and rain may have reduced the audibility of weka in other studies. The estimated probability of detecting weka was 60-80% (mean = 728). At least 3 nights at each listening station were necessary to improve the census accuracy. Call counts of weka at Rakauroa between 1993 and 1997 showed a decline in the number of weka.