Shorebird ecology and migration

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Shorebird ecology and migration
Pectoral Sandpiper Joe Liebezeit
Red-necked Phalarope Emily Weiser

• Jo Oldland

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What is a shorebird?
Snipe
Sandpipers
Curlews
Knots
Oystercatchers
Stints
Godwits
Plovers
Pratincoles
Avocets
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• Order Charadriiformes
• Suborder Scolopaci snipe, sandpipers, phalaropes
  etc
• Suborder Lari gulls, terns, skuas, auks, puffins
• Suborder Thinocori jacana, painted snipe,
  seedsnipe, Plains-wanderer?
• Suborder Turnici buttonquail
• Suborder Chionidi stone-curlews etc
• Suborder Charadrii avocets, stilts,
  oystercatchers, plovers, lapwings

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Shorebird species in Australia

• 18 residents

Hooded Plovers by Glenn Ehmke
36 migrants
Bar-tailed Godwits by Glenn Ehmke
24 vagrants
The Australian Pratincole is known to migrate
to islands north of Australia
Dunlin by Alexandre Andreev
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Sanderling Hooded Plover Glenn Ehmke
Sooty Oystercatchers Chris Tzaros
Lathams Snipe Chris Tzaros
Rocky shores
Freshwater wetlands
Sandy beaches
HABITAT TYPES
Intertidal mud/ sandflats
Grasslands
Inland salt lakes
Asian Dowitcher Rob Clemens
Masked Lapwing Chris Tzaros
Banded Stilt Glenn Ehmke
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Many are migratory
East Atlantic
Mississippi Americas
Central Asian
Black Sea Mediterranean
East Asian-Australasian
Atlantic Americas
Pacific Americas
East Africa-West Asia
World flyways used by migratory shorebirds
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East Asian-Australasian flyway
Birds breed in Siberia, North China and Alaska in
June and July
Stopover at staging sites in Yellow Sea
Migrate south to Australia New Zealand
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Migrant Breeding

• Migrants to Australia breed in Northern Asia or
  Alaska
• Two exceptions

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Pacific Shorebird Migration Project set out to
test the theory of Godwits non-stop flight Team
of collaborators from USA and NZ tagged 16
Bar-tailed Godwits with satellite transmitters in
Feb 2007 in NZ. Mid March birds left NZ. A7
flew to China, where she re-fuelled for five
weeks China to Alaska. Departed Alaska 31st
August. Battery running very low!
Global flight record of 11,600 km 9 days
duration Total migration (round trip) 29,000 km
Three countries
Arrived New Zealand midday 7th September.
Battley (2008) Long-haul flights, Godwit style.
Wingspan, 28.
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• 15 godwits fitted with satellite transmitters at
  Broome in Feb 2008
• Birds flew nonstop to Yellow Sea, spent 6 weeks
  there, then departed for Alaska and Siberia
• Returned to Broome later that year

A7 in the hand Adrian Boyle
Released A9 in flock Jan van de Kam
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Geolocator Trials on Ruddy Turnstones

• In March-April 2009, the VWSG AWSG attached
  geolocators to 8 Ruddy Turnstone 6 on birds
  captured at Flinders and 2 in SE South Australia.
  
• Weighing 1.1g, geolocators record light levels
  which can be processed to give location latitude
  and longitude
• Requires unobscured view of natural light level
  at dawn and dusk.
• Hoped to provide with significantly more
  knowledge of Ruddy Turnstone migration and
  breeding movements
• Challenge is the birds need to be recaptured to
  get the data!

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Exciting results

• 4 of the 6 geolocators applied at Flinders
  retrieved by Jan 2010.
• All 4 flew nonstop 7,600 km to Taiwan in 6 days,
  before flying to northern Siberia via eastern
  Asia
• Bird 4 (9Y) had an unexpected return migration
  route to Flinders via the western Central Pacific
  - a 27,000 km round trip migration
• April 2010 60 more geolocators fitted to Ruddy
  Turnstone in Vic, SA King Is Greater Sand
  Plovers in Broome Sharp-tailed Sandpipers at WTP

Migration route recorded by geolocator for Ruddy
Turnstone with leg flag 9Y. This bird departed
Flinders (Victoria) 27 April, 2009 and returned 8
December, 2009 after a journey of 27,000kms.
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Why migrate?

• Did ice ages prompt evolution of migration?
• Harsh winters forced birds to leave tundra and
  return to breed in summer
• Extended time away from tundra forced adaptation
  to new niches mudflats wetlands
• Feeding tools evolved to specific food resources
  in wetlands over time ? resource partitioning
• Ice ages changed position of wetlands and
  mudflats by moving oceans waders moved
  accordingly
• Many waders now locked into their particular
  feeding niche feeding tools are too specialised
• This theory doesnt fully explain the pressures
  behind the birds reaching the southern hemisphere

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During non-breeding season
weight gain mid-season to departure

• Enlarged feeding organs allow more food to be
  digested
• Increased feeding rate leads to extra fat storage
• Amount of fat influences migration range

Photo Dean Ingwersen
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Before departure

• Decrease in size of feeding organs
• Flight muscles increase
• Heart grows to supply oxygen
• Blood thickens
• Non-essential leg muscles decrease
• Complete moult of all flight feathers, moulting
  into breeding plumage
• Females store extra calcium for egg laying on
  arrival

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Migration

• Departure time depends on length of migration and
  climate at destination (timing of arrival crucial
  for breeding success)
• Larger species tend to take long haul flights,
  smaller species make island hops
• Average 20-25,000 km round trip
• Average 6000 km non-stop flights

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In flight

• Fly at around 2-3 km altitude, at speeds of
  30-60km/hr
• Flying V formation most efficient
• Change direction to take advantage of prevailing
  winds
• Decrease in weight due to energy consumption
• Flight muscles atrophy as decrease in weight
  makes them redundant
• Heart muscle atrophies as muscles decrease
• Flight feathers wear out
• Brain chemistry changes to allow non-stop flight
  for days at a time

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Navigation

• STARS - recognise rotation of stars
• SUN - shorebirds can navigate using internal
  clock, calendar, and the position of the sun
• COMPASS - follow lines of polarity in the sky,
  and are thought to be able to sense magnetic
  directions
• MEMORY shorebirds follow landmarks such as
  rivers, mountain ranges, and roads
• INSTINCT - parents leave breeding ground before
  young, which then have to make their own way
  south

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Arrival on the Tundra

• Pairs spread over millions of square km,
  densities of lt1-20 pairs/km2
• Tundra breeders sandpiper and godwit species
• Boreal forest breeders Common Greenshanks
• Steppe breeders Grey Plover

Tundra region (orange)
Emily Weiser
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Why the tundra?

• Tundra is the ideal place for breeding in
  northern summer
• Long days mean high productivity
• Clouds of insects dont even have to move to
  feed
• Long views predators cannot sneak up easily
• Camouflage essential breeding plumage the
  perfect match for Tundra vegetation

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Breeding season

• Birds usually arrive when snow disappears late
  May/early June
• Courtship and pair formation begins on arrival
• Most shorebirds nest on the ground
• Eggs laid 5-8 days after arrival
• Chick hatching timed to correspond with peak
  insect abundance
• Chicks are precocial when hatched, parents brood
  but do not feed

Whimbrel at nest
Hatching godwit
Godwit chick
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Arrive, display, mate
Eggs
Hatch
Fledge
6 weeks!!
Pectoral Sandpiper display
Grey Plover nest
Pectoral Sandpiper chicks
Bar-tailed Godwit juvenile
Pictures Emily Weiser
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Leaving

• Parents stay with chicks for three weeks, then
  leave for southern hemisphere, leaving young
  behind
• At six weeks old, the young must leave or freeze
  (snow starts to fall)
• Young fly unaided all the way to the southern
  hemisphere
• Adults arrive in Australia Sept-Oct
• Juveniles arrive November onwards

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On arrival

• Birds are exhausted on arrival (have landed beak
  first!)
• Basically land and start feeding
• Spend 5-6 months in south over Austral summer
• Depart for northern hemisphere Feb-Mar
• In most species juveniles dont return north with
  their parents, staying in Australia until 1-4
  years old.

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Residents

• Plovers, dotterels, lapwings, oystercatchers,
  stone-curlews

Hooded Plover Glenn Ehmke
Red-capped Plover chick
Pied Oystercatchers Glenn Ehmke
Beach Stone-curlew Keith Lindsay Fisher
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Residents - Nomadic
Banded Stilt - Glenn Ehmke
Australian Painted Snipe- Adrian Boyle
Black-winged Stilt - Danny Rogers
Red-necked Avocet - Chris Tzaros
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Daily movements

• Feed according to tide low tide increases area
  for feeding and behaviour of prey
• At high tide birds roost
• Shorebirds feed day and night
• Smaller birds must feed for longer

Roebuck Bay roost - Rob Clemens
Red-necked Stints Chris Tzaros
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Polychaetes
Bivalves
Photos by Sabine Dittmann
Examples of shorebird prey items
Gastropods
Crustaceans
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Feeding strategy I Sandpiper strategy

• Small eyes set high in head, long bills
• Slow movements, probe below the surface, tactile
  sense, cannot see prey
• Some sandpipers (e.g. Great Red Knots) sense
  prey using pressure sensitive pits on their bills
  (Herbst corpuscles)

Curlew Sandpiper Dean Ingwersen
Red Knot Andrew Easton
Ruff Dean Ingwersen
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Feeding strategy II Plover strategy

• Plovers have large eyes, short, blunt bills
• Run and stop, visual sensing of prey
• Pick food off the surface, often through ambush
• Eyes work even at night
• Some switch from plover strategy to sandpiper
  strategy (sense prey by touch) in total darkness

Double-banded Plover Dean Ingwersen
Greater Sand Plover Dean Ingwersen
Red-capped Plover Chris Tzaros
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Each species bill, feeding locality and diet
varies at least slightly from all other species
Resource Partitioning
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This project is supported by Birds Australia and
The Australasian Wader Studies Group, through
part funding from the Australian Governments
Caring for our Country

• Photos Emily Weiser, Steffen Oppel, Chris
  Tzaros, Dean Ingwersen, Rob Clemens, Adrian
  Boyle, Chris Sanderson, Jan van de Kam, Glenn
  Ehmke, Lainie Berry, Alexandre Andreev, Sabine
  Dittmann, Chris Sanderson and Dean Ingwersen
  contributed content

Black-tailed Godwit Chris Tzaros