Where she talks about how multiple nations and habitats need to cooperate to help these champion migrants.

In this episode, Dr. Yaara Aharon-Rotman speaks about long distance migration, mainly among shorebirds but also passerines.  We have explored migratory shorebirds before in Episode 43.  Here, Dr. Rotman talks about how national borders don’t apply to migrating birds and how we all need to cooperate to help them along. 

Bio of Dr. Rotman supplied by her:

Originally from Israel, Yaara has completed her PhD in Deakin University, Australia where she studied long distance migratory shorebirds. Inspired by the long migration of her studied species, she than joined research labs in Israel (to work on migratory passerines), China (where she worked on a vulnerable Asian habitat for migratory geese) and Australia, her current home where she study torpor in local and migratory species as a postdoctoral fellow at the University of New England. Her main interest focuses on how animals, mainly migratory species, respond to challenges, and specifically, their physiological adaptation to global changes. If she is not looking for birds in the field or analysing data in her office, you can find her inone of the National Parks around Armidale with her family, or at the boxing ring!


About torpor


1:00: How she started to work with birds ((by chance, I just wanted to do something different, and found myself doing a PhD on migratory birds)

2:30 What are the species that she studied? They fly 30,000 kms every year.  Why do they do this? To help with thermoregulation, food abundance, for better breeding conditions

4:00 What is thermoregulation? Endotherms are humans, birds, mammals, animals.  Constant body temperature.  We expend energy to maintain stable body temperature.  Reptiles are ectotherms– they use the sun to warm up.  Birds migrate to help thermoregulation.

5:20 Birds put on weight to aid thermoregulation.  She talks about the ruddy turnstone.  100 to 120 gms normally.  Before migration, for two months, they constantly eat and become 200 gms.  Double their weight.

6:30 What are some examples of extreme migrations birds are doing (bar tailed godwits, ruddy turnstones, redknot, great knot, arctic tern).  Bar tailed godwit stops in South and North Korea.  On the way back they fly non stop from Alaska 

8:37 Really cool animation about how bar tailed godwits use the wind to cross the oceans and arrive in synchrony with the seasons.  They arrive just in time when the snow thaws and there is a spurt of vegetation. In September, they just cross the ocean directly.

9:30 Ruddy turnstone.  Champion migrators.  South Australia, to Taiwan to China to the Russian Arctic.  She talks about how they capture data.  200 kms of error.

Ruddy turnstone

11:00 What is so great about these champion migrators? They use strategies.  Double their weight.  Burn the fat during migration.  Use wind to assist them in migration.  They fly nonstop for days.  Ruddy turnstone flies nonstop for 6 days from Australia to Taiwan.  Half of the brain is asleep while the other half is awake.  Before they start the migration, they shrink organs that are useless.  For example the liver.  They only need muscles for migration.  When they arrive, exhausted, they rebuild their liver, sexual organs, etc.  Fat and muscle are the main thing.  They eat specific types of food for migrations.  The more we learn we learn that we don’t know.

14:00 Time and energy of migration.  Spend winter in South Australia.  But the habitat deteriorate so they don’t have enough food to put on the fat for migration.  She talks about Africa and drought and how birds find it difficult to find food.  The timing has to be exquisitely timed to arrive just in time for food abundance.  Snow hasn’t started to melt and it is freezing and they don’t have anything to feed on.  What if the snow thaws earlier? The birds arrive and miss the peak of food availability.  

16:50  The complex factors.  Living seasonally for a bird.  They are migrating from Australia or South Africa to the Arctic or Austria.  They have no idea what they will find when they show up after migration.

17:44: Passerine birds.  Eurasian black cap.  Warbler.  Shrikes.  They fly from South Africa to Europe.  These birds stopover in Israel.  Banding of birds happens in Israel.  Drought in Africa caused the birds to come to Israel very late.  Conditions in the South of the hemisphere affect the timing of when they start migrating.  Long and complex link that we need to factor.

20:00 What happens if one migrating site deteriorates? Are the birds able to skip this sites? She talks about how modelling helped them figure out how different species deal with habitat changes.  Redknots numbers declined because lots of changes happened in the yellow sea.  They lost habitat and so species that were dependent on the Yellow Sea stopover declined. What are the main challenges for migratory birds with the changing climate (mismatch, because they rely on multiple sites along the route with varying conditions)

22:30 The cues that birds use to start migration.  In April, according to humidity, position of the sun.  They know that they have to go up north.  Internal and external cues.  

23:30 About her experience working in China in Poyang Lake.  How was the experience to work in China on an international important wetland for many species of migratory waterfowl? Dams were built.  Unique thing is that seasonality changes the water level.  During winter, water level drops and exposes a lot of food species for birds.  In summer, water level rises and therefore covers all the food.  China still hasn’t built the dam along the Yangtze River.  It is just one link– but if we destroy one link it will affect the whole system.  

28:00 Culture towards birding in Australia, Israel, China.

30:00 What she learned from studying champion migrators

31:00 Torpor in local Australian birds.  New South Wales.  How birds adapt to cold conditions? Yellow robins and treecreepers.  How they adapt to sub zero conditions? She talks about a previous guest, Dr. Anusha Shankar.  Birds drop temperature by 7 or 10 degrees.

She talks about the study of Eastern yellow robins.  Do they undergo torpor only on certain nights? When it is very cold? How often they use this strategy? In Western Australia for instance, these same birds didn’t use torpor because it isn’t as cold.  What are the cues that cause these birds to use torpor?

36:00 Differences between shorebirds and passerine migrations? Size isn’t the factors.  Little stints are tiny shorebirds.  Differences is habitat requirements.  Passerines migrate from South Africa to horn of Africa to sub-Sahara (rich area), cross the Mediterranean Sea, or via Israel to Europe.  Passerines are less limited in their choice of where they can stopover.  Shorebirds need shores.

37:00 Why is the shorebird migration north-south? Some shorebirds migrate from the breeding area in the Arctic to the equator and don’t go much below.  But they cross the equator to get temperate weather and food abundance.  Not many birds do horizontal migration.  They do north south.

38:30  Ruddy turnstone is her favorite.  The anecdote of how her banded ruddy turnstone came back all the way from the Arctic to that same small beach in Australia.

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