Every year Red Knots accompanied by Ruddy Turnstone, Sanderling and other waders make the northward journey up the Eastern coast of South and North America. This year Chris and I will be involved with the monitoring process at one of their Spring migration stop overs. The birds converge on Delaware Bay and time their stay to capitalise on the food available from spawning Horseshoe Crabs.
Just as the Horseshoe Crab eggs draw the birds, the migrating waders attract a large team of scientists, environmental workers and volunteers from across the world to participate in a study that has spanned 20 years.
The first studies began in 1997 at which time the unregulated collection of spawning Horseshoe Crabs for bait was commonplace. Following media coverage of this,the work being done on the beaches and reports of wader population decline, the practise of Horseshoe Crab harvesting was banned.
Since then fencing off of key areas at key times of year also worked to protect the waders and crabs and there are now various community projects such as 'return the favour' where volunteers turn over stranded crabs at night, allowing them to return to the sea and spawn again, and beach stewards protect the beaches by working to ensure that the restricted areas are upheld.
The people at the core of these studies were instrumental in organising beach restoration after Hurricane Sandy in October 2012. Key beaches had been left without sand, rendering them unsuitable for spawning, but the scientists worked with local people to coordinate an intervention to source sand involving a range of people from experts on sand grain size, to local business men and organised local companies to supply sand, making it possible to restore 2.6 miles of beaches to the correct conditions so that crabs could spawn successfully and birds had eggs to forage on.
Studies have focused on Horseshoe Crabs and birds. Data is being used to inform population numbers and changes, timings of migration of short, medium and long distance migrants and general bio-metric indicators such as wing, bill, head and bill length and weight.
The Delaware Bay is affected by economic pressures, with Horseshoe Crabs taken to be bled for Lysate (used in the cosmetics industry) and moves to expand the aquaculture for producing of oysters. This a concern, as siting of oyster racks on the inter-tidal mud flats poses a threat to waders foraging in that these areas are avoided by the birds and may also affect Horseshoe Crab movements.
There are other studies along the Atlantic flyway and some birds from Tierra del Fuego, Argentina, Brazil, Chile, Peru and SE USA can be identified from metal rings and coloured flags. Birds have also been fitted with geo-locators, but the data can only be retrieved when the bird is recaptured and the equipment removed.
Chris and I will be doing counts and recording colour rings and flags in the field mostly, but we hope to get on to some catches and work with the long established team on this most worthwhile project.
North Reed's Beach,
