Magpie predation on songbirds


Songbird nests near to magpie nests were more likely to be predated. © Peter Thompson/GWCT


KEY FINDINGS


We found that artificial nests were heavily predated by particular individual territorial magpies. One third of 520 artifi- cial songbird nests placed in hedgerows on a mixed farmland site were predated. At least 45% of these were predated by medium-sized birds. Cameras on one third of these nests identified magpie in 90% of cases.


The data also suggest that songbird nests near to magpie nests were more likely to be predated.


Lucy Capstick Rufus Sage Joah Madden


Dunnock. © Peter Thompson/GWCT 20 | GAME & WILDLIFE REVIEW 2016 www.gwct.org.uk


To examine any potential difference in nest predation behaviour between territorial and non-territorial magpie individuals, we placed artificial nests in hedgerows adjacent to active magpie nests (magpie nest present) and at least 200 metres from magpie nests (magpie nest absent). This is a recognised technique used to gain an understand- ing of the pattern of nest predation and the identity of nest predators without disturb- ing natural nests. Both old songbird nests and man-made nests were baited with real and wax-filled quail eggs and approximately one-third of nests were also monitored by motion-activated trail cameras. A predator attacking a wax egg leaves an imprint, such as a beak or bite mark, and can therefore be identified. At each site, five nests were placed along a hedgerow (hereafter, a transect) and left


for five days. In 2015, three blocks of eight transects (four in magpie nest present sites and four in magpie nest absent sites) were set out, only once, in May and once in June. In 2016 transects were set out in five blocks of four (two in magpie nest present sites and two in magpie absent sites) each repeated four times from April to July. In total 520 nests were placed across the field site, a 1,500ha area of mixed farmland in Warwickshire.


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