Feathers in the mud

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Every year, millions of shorebirds undertake one of the world’s most spectacular migrations. Bird after bird travels half way across the world, from breeding grounds in the Arctic, to non-breeding grounds throughout the Southern hemisphere. In fact some species, such as the Bar-tailed godwit are able to do this in a single flight. A female bird named E7 set the record by flying an amazing 11,700 km in 6 days from Alaska to New Zealand.

However, shorebirds are not only one of the longest migrating birds, they are also some of the fastest disappearing. In fact some species have declined by almost 80% over the last 15-20 years. And the truth is, we do not know exactly why. Many factors are probably influencing these declines.

Below: Ruddy Turnstone before and after migratory weight gain

Ruddy-turnstone-on-mussel-bedruddy-turnstone-46392

Migratory behaviour

For species which fly such long distances, fattening up is crucial. Think of it as doing 293 marathons in one go. You would need to eat a lot, and so do birds. In fact, most species increase their weight by 50 to 80% just before migration. All of which is lost during flight. Strategically placed feeding sites are therefore absolutely necessary for most species to survive migration.

Not only that, shorebirds also feed on worms and molluscs in the intertidal zone, and are dependent on low tide for their meals. As soon as the tide comes in, they are forced to off to roost. Therefore any threats affecting their feeding will severely impede their migration efforts, and ultimately reduce survival.

Loss of stopover sites

The Yellow Sea is one of the most important stopover sites for shorebirds within the East Asian Australasian Flyway. Not only because of it’s a strategic location, but also because of the good quality food it provides. Yet the Yellow Sea is also in one of the most highly populated and developed areas of the world. Reclamation is occurring at staggering rates throughout the flyway, and mudflats are being lost faster than even the Amazon rainforest. The latest assessment of intertidal mudflats in the Yellow Sea has revealed the loss of 65% of their original extent in the 1950s, when they were estimated to cover 1.12 million hectares of the coastline.

There are two main reasons for this. Firstly, there has been a decrease in sedimentation due to reduced deforestation and increased damming. Secondly, large areas are being reclaimed for development. The issues are overall complex and require international collaboration. I will not go into them in more detail, but more can be read here and here.

Bar-tailed-godwit-exhausted-after-migration

Hunting

Hunting is poorly understood in the East Asian-Australasian Flyway. It certainly occurs, but to what extent? Where is it occurring, and how it is impacting shorebird numbers, survival and reproduction? Just getting more data to understand how much this might even be of an issue, could help set sustainable hunting quotas to minimise losses..

Disturbance

Disturbance in itself is a small scale problem. However, repeated disturbance can prevent shorebirds from gaining the necessary weight to complete migration. Because of the tidal cycle, shorebirds have limited feeding opportunities, and are very sensitive to disturbances. They have very few places to roost, and if disturbed, are either forced to fly around in circles until the disturbance has left, or fly to the next suitable habitat, sometimes kilometres away, wasting precious calories.

Dogs, vehicles and people all cause disturbance, yet are easily mitigated by taking the time to walk around flocks and make sure dogs are on leashes.

Increasing awareness about shorebirds

This may seem trivial, but few people even know that shorebirds exist, let alone that they migrate tens of thousands of kilometres. Taking a moment to just marvel at them, and educate others about the issues surrounding their conservation could make a world of difference.Simple steps, such as keeping dogs on leashes, avoiding flocks of birds, supporting your local wader study group and lobbying both local and international politicians can all help. Particularly forcing new developments to mitigate their impacts by creating artificial habitats for birds, if nothing else. Artificial wetlands are certainly possible to engineer and create with the correct know how.

Getting involved

Finally, there are a number of organisations you can get involved with. Including your local wader study group, the flyway partnership and birdlife. All of these need funds to carry out advertising campaigns, improve habitat and fund research:

You could also keep a bird list on ebird and contribute your data to science.

Only 300 spoonbill sandpipers are left in the wild… Here’s a lovely little animation made by children from around the flyway:

Spoon-billed-sandpiper-chick-in-hand

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