Paul Ralph, a Dargaville-based Pest Management Officer for the Northland Regional Council (NRC), says the magpie’s seven-month breeding season typically runs until the end of January.
Mr Ralph says although the Regional Council does not keep records of magpie attacks, “nesting magpies can – and do – attack people and can injure them”.
“Magpies are territorial and aggressive and are also known to attack, kill, or drive off other birds, including native species, again especially during the breeding season.”
Magpies (Gymnorhina tibicen) were introduced to New Zealand from Australia in the 1860s in a bid to combat pasture insects and are now found throughout Northland. They feed on a variety of insects, seeds and vegetable matter and are notoriously difficult to control.
Mr Ralph says the NRC took part in a four-year study of magpies several years ago. The study found magpie reinvasion was “endless and eradication was never achieved, in part because the intelligent birds are such quick learners”.
He says two native bird species that can be badly affected by magpie attacks are tui and kukupa (native woodpigeon).
“This problem can be especially bad in a fragmented landscape with isolated native forest fragments as the nearest escape, cover or safe feeding site for these native species may be several kilometres away.”
Mr Ralph said the 2000-2003 study showed while it is worth controlling magpies at particular sites where they are known to be chasing tui or kereru away from preferred food sources, controlling all magpies across the whole landscape “is likely to be a waste of time and effort”.
He says habitat loss and other predators (including rats, stoats, weasels, feral cats and possums) are more likely to limit tui and kukupa numbers.
Options for magpie control include shooting or traps, but as the birds learn quickly, “there is usually only one chance to capture or destroy them”.
“If an initial attempt fails, a magpie will be very difficult to get second time around.”
Mr Ralph says those wanting to shoot magpies can use a recording of a magpie distress call, or a live trapped magpie, to lure the target bird.
However, a firearms licence is needed and firearms have to be used with extreme care, especially if there are other people or animals in the vicinity.
Trapping options include the use of live capture traps, which are cages with a spring-loaded door which is tripped by the bird when it enters.
“Magpies can be attracted by pre-feeding first with dog roll or mutton fat outside the trap.”
A captured bird can then be used to lure others by placing it in a compartment inside the trap.
Mr Ralph says further advice on magpie and other animal pest control is available from Northland Regional Council offices at Whangarei, Kaitaia and Dargaville.