By Shelley Topp
Silvereyes, one of New Zealand’s most abundant birds, are in decline nationally, a new report shows.
The report compiles data from Landcare Research’s annual New Zealand Garden Bird surveys, during which information has been collected from more than 31,000 gardens nationwide since 2007.
The surveys are done to estimate how bird populations are changing in New Zealand.
“Birds act as backyard barometers, telling us about the health of the environment we live in and we should be listening,” Landcare Research ecologist Dr Catriona MacLeod says.
The surveys show that silvereye numbers have declined 43 percent nationally.
In North Canterbury, the decline of the birds, also known as waxeyes, is more pronounced, with a 49% drop in numbers in Rangiora, Amberley and Kaikoura; 52% in Woodend; and a 61% fall in Oxford.
A research associate for Landcare Research’s biodiversity and conservation team, Eric Spurr, acknowledges that pockets of local abundance will always occur, particularly where ideal habitats or feeding opportunities exist. But he is unsure why the overall silvereye population is in decline.
“It may be that the increasingly warmer winters mean that they are staying in the forests if food is plentiful instead of coming into town gardens in search of food.”
The report is a forerunner to this year’s annual New Zealand Garden Bird Survey which begins on June 30 and ends on July 8.
“People pick one day and spend one hour in their garden counting the highest number of bird species they see at any one time,” Eric says.