Beach House Chicks

What could be better than a nice view of the surf, a little sand — and survival? Australian researchers have found that providing threatened shorebirds with simple A-frame “chick houses” made from plywood can dramatically increase the survival of young birds. But they aren’t sure exactly why the avian architecture helps.

The Hooded Plover (Thinornis rubricolli) is a striking black-headed, red-eyed shorebird that can be found along beaches on Australia’s southern coast. Researchers estimate that less than 10,000 of the birds exist, and their population has been dwindling due to habitat loss, predation, and the trampling of surf-side nests by off-road vehicles and livestock. Protecting young chicks is a particular problem because they roam along the waterline in search of food, making it impractical to use the fences or protective netting that has helped other kinds of fledging shorebirds make it to adulthood.

To see if a little bird-friendly construction might help the young plovers, Grainne S. Maguire of Birds Australia and colleagues from Deakin University in Victoria, tested three kinds of beachfront houses, eventually settling on a simple A-frame about the size of large shoebox. Then, they randomly distributed the shelter to territories occupied by plover families along several popular tourist beaches in southern Victoria. Finally, they took measurements designed to reveal how often the young birds used the shelters, how the constructions stood up to shifting sands, predators and beachgoers, and whether they helped insulate the birds from hot and cool weather. They also compared the survival of the birds with the A-frames to those without.

The results, published the current issue of Bird Conservation International, are striking. In one sample, the survival rate of chicks with beach houses was 71.8% higher than those without. In a second, larger trial, shelters increased survival by 42.8%.

Both numbers suggest a building boom could help sustain Hooded Plover numbers, the authors write. Exactly why the plywood homes help the plovers isn’t clear, however. The researchers speculate that the A-frames may help the chicks stay cool when the weather is hot (or warm when its cool), shelter them from predators, or enable them to avoid getting crushed. Sifting out the exact answer, however, will take more than day at the beach. David Malakoff

Source: MAGUIRE, G., DUIVENVOORDEN, A., WESTON, M., & ADAMS, R. (2010). Provision of artificial shelter on beaches is associated with improved shorebird fledging success. Bird Conservation International, 1-14 DOI: 10.1017/S0959270910000420

Image © Ruslan Dashinsky