More research needed into Roebuck Bay feeding grounds

Dec 24, 2013 by Geoff Vivian
More research needed into Roebuck Bay menu options
A Red Knot foraging at Roebuck Bay. Credit: Ric Else, Birdlife Australia

Scientists at the Royal Netherlands Institute of Sea Research have been sampling Roebuck Bay's benthic marine life, as part of a larger study of migrating shorebirds.

The bay, in the Kimberley, is an important feeding ground for species such as red knots, great knots and bar-tailed godwits, which spend the northern winter there gaining weight and body condition.

The research was triggered by an interest in their foraging ecology.

For 16 years biologists Tanya Compton and Marc Lavaleye have collected mud- and sand-dwelling organisms that the birds feed on, such as bivalves, worms and crabs.

Dr Lavaleye gave the example of an organism that had been abundant in the mud of Crab Creek. "You had a bivalve of about two centimetres, it was very abundant, it's called the Siliqua," he says. "It was very good food for birds – especially the knots. They swallow them whole and they crack them in their stomach."

She says that on their latest trip they only found four Siliqua specimens, while at the same time finding peanut worms (Sipuncula) in almost every sample.

Dr Compton says it is too early to interpret these trends as either normal fluctuation or permanent ecological change.

"We can see trends but to understand what those trends mean you need to keep monitoring, you need to keep going there," she says. "Australian funds were limited for benthic work in Roebuck Bay this year, limiting the ability for a more expanded Australian collaboration."

She says a post-graduate student from an Australian university conducting extensive benthos sampling every year would contribute a better understanding of how shorebirds' food sources vary in time and space.

Dr Lavaleye says they made the first big survey of the Roebuck Bay tidal flats in 1997 after preliminary studies by students. Making a grid of a large area, they sampled mud at stations 200 metres apart, examining each with one-millimetre sieves. They repeated the survey in 2002 and 2006, and surveyed a smaller area this year. "And at the same time we initiated a program at two sites… to sample them monthly to see what would change over the time – and that program is still ongoing," Dr Lavaleye says.

Explore further: Zimbabwe to export elephants in population curb

add to favorites email to friend print save as pdf

Related Stories

Mayfly reintroduction to Michigan bay

Dec 05, 2013

Jerry Kaster's lifelong fascination with the mayfly could soon manifest itself in the most productive of ways: the successful re-establishment of an aquatic insect to the bay for which the animal was once ...

Bird buffet requires surveillance

Oct 28, 2013

The behaviour of semipalmated sandpipers (Calidris pusilla) feeding during low tide in the Bay of Fundy, New Brunswick, surprised Guy Beauchamp, an ornithologist and research officer at the University of Mon ...

Recommended for you

Wildlife groups seek help for California owl

Dec 24, 2014

Loggers cutting down forests burned in wildfires could bring about the extinction of California spotted owls, wildlife advocates said Tuesday as they sought protection for the birds under the federal Endangered ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.