Take the red knot. It’s a tiny shorebird that migrates from the tip of South America all the way to the Arctic Circle. One of the few stops on that marathon journey is Delaware Bay in USA, an estuary that offers a banquet for migrating birds.
Here’s what the red knots do. They eat like crazy in Argentina, and then they take off. They fly for up to 3,200 km without stopping, at altitudes of 6,000 metres where the air is incredibly thin. And as they fly north, there are a handful of specific places where they land reliably.
Brian Harrington is a retired biologist who’s studied red knots for 40 years.
“I think of stopovers as, like, stepping-stones. And very often, they’re places that are used by a variety of shorebirds – not just red knots – because they tend to be just a very, very highly productive little patch of the Earth. And the shorebirds know that’s a place they can find enough food to quickly put on the weight that they need to go to their next stepping stone.”
In Delaware they weigh as much as an avocado upon lift off. But they often weigh half that when they first show up, having burned off fat and sometimes even muscle during their inbound flight.
The meal of choice in Delaware Bay? Horseshoe crabs have been around for at least 300 million years. They lay their high-fat and high-protein eggs on the shores of the bay. It’s a feast for the red knots. Or at least, it was until recently. Over the last few decades, horseshoe crabs have become more popular as fish bait and for medical purposes. Fewer horseshoe crabs mean fewer horseshoe crab eggs, which means fewer red knots.
“It’s one of the fastest declines of a non-endangered bird that’s ever been documented,” says Harrington.
In the 1980s, Harrington counted 90,000 red knots on the Delaware Bay. Today there are fewer than 20,000. And the red knots depend on each of their stopovers spread out across the Americas.
(Source: Abridged from One Species at a Time, Ari Daniel, November 2016 and thanks to Encyclopedia of Life and Atlantic Public Media)
The red knots that migrate through Delaware Bay belong to the subspecies Calidris canutus rufa, which is listed under Appendix I of the Convention on Migratory Species (CMS). This means that the Parties to the Convention should endeavour to conserve and restore the habitats where the species lives.
Red knot. Photo credit Dick Daniels
The theme for World Migratory Bird Day on 10 May 2017 is "Their Future is our Future". The day will highlight the interdependence of people and nature, especially people and migratory birds, as they share the same planet and thus the same limited resources.
The 2017 campaign aims to raise awareness of the need for sustainable management of our natural resources, demonstrating that bird conservation is also important for our future. Bird population data can tell us a lot about how human activity is impacting the natural systems upon which we depend for our survival.
There are many different migration patterns. The majority of birds migrate between northern breeding areas and southern wintering grounds. However, some birds breed in the south and migrate to northern wintering grounds, or along lines of latitude to enjoy milder coastal climates. Other birds reside in lowlands during the winter months and move to higher altitudes for the summer.
Migration is a perilous journey and exposes the animals to a wide range of dangers, including human threats such as unsustainable hunting and collision with power lines. Some birds depend on specific sites along their flyway. The decline or loss of wintering and stopover sites, such as wetlands and estuaries, can have a dramatic impact on their chances of survival.
Flying long distances involves crossing many countries with differing environmental policies, legislation and conservation measures. International cooperation is required along the entire flyway of a species so knowledge can be shared and conservation efforts coordinated. The legal framework for this cooperation is provided by multilateral environmental agreements such as the CMS and the African-Eurasian Waterbird Agreement (AEWA).
Check out this slideshow to learn about more migratory birds: https://spark.adobe.com/page/AKfAuYfrlq0kF/
More about World Migratory Bird Day
The 2017 theme for World Migratory Bird Day is in line with the priorities and activities of its key partners: CMS, AEWA, BirdLife International, the East Asian-Australasian Flyway Partnership, Wetlands International, the International Council for Game and Wildlife Conservation and UN Environment.
World Migratory Bird Day was initiated in 2006 by CMS and AEWA and is an annual awareness-raising campaign highlighting the need for the conservation of migratory birds and their habitats. It helps draw attention to the threats faced by migratory birds, their ecological importance, and the need for international cooperation to conserve them.
CMS will be holding its 12th Conference of the Parties in the Philippines in October 2017 under the slogan "Their Future is Our Future - Sustainable Development for Wildlife and People".