Winter abundance and distribution of the skylark (Alauda arvensis) in Canterbury New Zealand : A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Resource Studies with Honours at Lincoln University

Abstract

There is little research on the skylark Alauda arvensis in New Zealand and nothing is known about its winter distribution and abundance. In New Zealand the skylark is a common and widespread farmland bird species. In contrast, in Europe, skylark numbers are drastically declining. Declines are believed to be related to changes in agricultural practices where factors such as increases in agrochemical inputs and a loss of mixed farming and rotational cropping have resulted in a reduction of suitable skylark habitat. The skylark is a specialised species that breeds and feeds in agricultural fields and other open country; it is sensitive to changes in the agricultural environment. The skylark is therefore a biological indicator of change in the agricultural environment. The study was carried out during the winter period of July and August 1998 on nine conventional and organic farms on the Canterbury Plains, New Zealand. A single visit was made to each of 85 randomly selected fields. Skylark densities were recorded in each field by walking a transect line and flushing and counting all the birds within a 70 metre belt. Within each field, habitat and environmental variables where recorded. These were: crop type, crop height, field size, percentage of crop cover, temperature, wind speed, weather conditions and the height of field boundary vegetation. Each field's farming system (i.e., organic and conventional) was also recorded, along with the previous crop and its management. There was a significant relationship between skylark densities and crop type, field size, crop height and field boundary vegetation. There was no significant association between any of the other variables recorded suggesting that there is no ecological relationship or that data and/or the recording period were insufficient to establish a significant relationship. The results from this study have identified the major variables influencing skylark distribution and abundance on the Canterbury Plains, New Zealand. The influence of these variables on skylark distribution and abundance on the Canterbury Plains is discussed in relation to parallel work in Europe.