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| Meet the Short -Tailed Shearwater, a smallish bird which travels 30,000 km a year from Southern Australian waters to Kamchatka in Russia and the Aleutian Islands and back via the Pacific Coast of North America |
These are the kinds of birds we mean when we celebrate World Migratory Bird Day this Saturday (10/10/2020). In the Northern hemisphere, you may have celebrated the same day on May 9 and even some of the same birds, because the movement of these birds depends on the seasons. In this case we‘re mainly talking about those which use the East Asian – Australasian Flyway which brings around two million birds to our shores each spring.
Many of them perform the most remarkable feats to get
here. The tiny Arctic Tern for instance, weighing only 113 grams (4 ounces), travels
a 71,000 km in zig zag route between Greenland and Antarctica.
The speed record holder is the Bar – Tailed Godwit which flies 11,000km non -stop from Alaska to New Zealand in only 9 days and does so without stopping to sleep or eat. Even non –flyers like the Adelie Penguins, manage to clock
up 17,600 Km by following the sun around
Antarctica. Read more here.
The main reasons for this are as follows:
- The loss of critical nesting and resting sites – sites which migratory birds have used for millennia. All kinds of land modification, but especially that involving marshland and estuaries diminishes the favoured habitat of migratory birds. However, it is the building of seawalls on both sides of the Yellow Sea which seems to have had the most profound effect.
After the building of South Korea’s Saegmamgeum Seawall, which
enclosed an area which supported 40,000 birds, the Great Knot population reaching Australia declined by a 20%. Almost 70% of China's coastline is now walled with land reclamation proceeding at a rapid pace. This has had disastrous consequences for migratory shorebirds such at Bar -Tailed Godwit, putting both subspecies on Australia's threatened species list. Read more here.
- The hunting of migratory birds which have until now come reliably
to certain locations, has also contributed to their decline. In some cases it
is their food which is sought, such as the horseshoe crabs whose eggs are a
major food source for the Atlantic Red Knot during its migration from the
Canadian Archipelago
to the tip of Argentina. Over -harvesting of the crabs has led to decline in a subspecies, the
Rufus Red Knot which is now listed as endangered in the USA.
- Pollution from industrial and agricultural activity obviously affects migratory birds as well.
Plastic pollution, both fragments and nano particles were recently found to be
even more concentrated- in the Arctic and those other
high latitude locations favoured by these birds, than in the world’s five
garbage patches, though the effects of that have still to be studied. One
aspect which may not be as obvious is light pollution. Nevertheless, light from
industrial activities and residential areas, even from tankers and oil and gas
platforms, can disorient seabirds and shorebirds, causing injury and death, or disrupt feeding and migration patterns and
can even affect their internal positioning systems, so that they can no longer find their way back to ancestral nesting sites. For more information on this as well as ways to mitigate these effects see the National Guidelines about Light Pollution.
- Climate Change is already
altering the delicate balance between
the hatching of insects and the hatching of young birds, leading to lower
numbers and smaller birds which are not as resilient. A study of Black Guillemots in Alaska showed that melting sea ice made their food less accesible, which is likely to cause similar problems. Curiously,
Antarctica’s Adelie Penguins appear to be increasing in number which is believed to be due to the loss
of major competitors for food, but even this is not necessarily a good omen but rather a further indication that an
existing balance has been upset.
Rising sea levels and stronger storm swells undoubtedly affect breeding sites too, as if they weren't already threatened by coastal development, growing numbers of humans, activities such as boating, and fishing, jet boats and off -road driving and predation by domestic animals such as dogs and cats.
While large scale habit loss in South East Asia may be a primary cause of decline, incremental loss of habitat through residential and infrastructure development such as ports is certainly a factor in Australia. This will not be helped by proposed changes to our environmental laws (see last week's post), which leaves such matters up to the states. Read more here.
How you can help
1. Insist that our governments not only enact, but enforce legislation to protect important sites and work towards co -ordinated action between countries to ensure safe passage for birds along the entire Flyway.
Although all 22 countries along the Flyway have signed agreements to protect migratory birds and their habitat, this has not been sufficient to halt their decline. The current proposals to cut “green tape’ in Australia will make things infinitely worse.
As predicted by Samantha Vine, head of Conservation at Birdlife Australia, developers are already straining at the bit and pressuring the Tasmanian State Government to allow major development on Ralph’s Bay an internationally recognised shorebird site and also home to the endangered handfish.
Queensland has approved the building of a coal port at Abbot Point which supports 17 migratory shorebirds and the expansion of port facilities at Gladstone where endangered birds such as the eastern Curlew and the Bar - Tailed Godwit make their home.
NSW too, is expanding both residential and port facilities in the Hunter Estuary and in the Great Barrier Reef Coastal zone, both of which also pose risks to migratory birds. "It's really death by a thousand cuts," says Professor Richard Fuller. Read more here.
2. Stop using plastic. Refuse it, ban it, recycle it and at the very least put it in the bin.
3. If you are on the beach, be careful where you tread and make sure your dog is on a leash. Councils could do more to too to protect critical habitat and nesting sites with fencing and signage to ban dogs not on leads or activities such as four -wheel driving and boating around nesting sites.
4. Help our scientists by participating this year’s Aussie Backyard Bird Count during National Bird Week from October 19th to the 25th.
5. Join a group such as Birdlife Australia - volunteer, donate or take part in some of their other activities – learn how to identify birds and how you can help to prevent their extinction.
6. Check out the UN website about migratory birds for other ways to celebrate the day and help the world’s birds.
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