Some songbird nests are especially vulnerable to magpie predation

MAY 29, 2019

by University of Exeter

A new study has revealed a range of factors that cause a variation in predation by magpies on farmland songbirds.

Researchers from University of Exeter and the Game & Wildlife Conservation Trust (GWCT) placed 460 artificial nests on typical farmland in Warwickshire to study predator behaviour.

They found magpies were the most common predators, accounting for 70% of visits where the predator could be identified.

Nests inside magpie breeding territories were predated by magpies more often, especially late in the season when magpies themselves had young in their nests.

Intriguingly, some specific nest locations were repeatedly highly predated.

The findings come amid controversy over the rules governing which birds can be killed to protect wild birds, crops and livestock.

"This works suggests that, although most nest predators are magpies, not all magpies are nest predators," said Dr. Joah Madden, of the University of Exeter.

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It's a bird–eat–bird world

January 24, 2019, University of Queensland

Baby birds and eggs are on the menu for at least 94 species of animals in Australia's forests and woodlands, according to new research from The University of Queensland.

Ph.D. candidate Graham Fulton reviewed 177 existing bird studies across the country, identifying Australia's most prolific nest predators and the factors affecting nest attacks.

"Predators attacking bird nests – known as nest predation – is the leading cause of nesting failure," Mr Fulton said.

"Predators are always looking for their next meal and now we know who Australia's common culprits are.

"In the reviewed research, 94 nest predators – from birds to reptiles to ants – were found to be attacking both natural and artificial nests.

"If you take out the artificial nests, it's 69 species, and from that data there's a clear dominant nest attacker in the Australia's natural environment – the pied currawong."

The pied currawong was found to be taking eggs and young from 29 different bird species; followed by the square-tailed kite (18 species), the tiger snake (15 species), the laughing kookaburra (10 species) and the grey strike-thrush (eight species).

"These five nest predators were recorded as attacking a whopping 40 per cent of the prey measured by the number of prey species taken," Mr Fulton said.

"The other 60 per cent of predation was carried out by the other 64 species, which included, by order of importance: birds, mammals, reptiles, frogs and ants."

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Hidden in plain sight: Amazonian bird chick mimics toxic caterpillar to avoid being eaten

Date:

February 23, 2015

Source:

University of Chicago Press Journals

In a study published in the January 2015 issue of The American Naturalist, Gustavo A. Londoño, Duván Garcia, and Manuel Sánchez Martínez report a novel nesting strategy observed in a tropical lowland bird that inhabits an area with very high losses to nest predators.

How can tropical birds cope with the high rates of nest predation that are typical in most tropical habitats? Are there nesting strategies that allow tropical birds to escape predators such as birds, mammals, and snakes that regularly eat eggs and nestlings?

During the fall of 2012, while working on a long-term avian ecological study, the researchers discovered the second nest ever described for the cinereous mourner (Laniocera hypopyrra) at Pantiacolla Lodge in the upper Madre de Dios River in southeastern Peru. They observed that upon hatching, the chicks had downy feathers with long orange barbs with white tips, which was very different from any other nestling they had observed in the area. The peculiar downy feathers attracted their attention, but the nestling behavior provided a more important cue. While researchers were collecting morphological measurements, the nestling started moving its head very slowly from side to side in a way typical of many hairy caterpillars. While working in the area, the investigators found a poisonous caterpillar with similar size and hair coloration as the nestling. Therefore, the researchers suggest that this is an example of Batesian mimicry in which the nestling tricks predators into thinking that it is a toxic, spiny caterpillar rather than a highly edible nestling.

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