The End of the 2008 Southern Cross Fall Migration

Our last migrating peregrine, Elizabetha, has finally arrived back at her austral range at La Trinchera in south-central Chile. After the longest recorded GPS fall migration for any peregrine, 94 days, she returned “home” to the Putu dunes on Christmas Day, 2008.
This is another example of a migrant North American peregrine engaging in what we are now calling an “extended migration”, meaning she took way longer to get there than we thought she should. The conventional wisdom has always been that migrant peregrines raced back to their austral ranges to be the first to lay claim to a “wintering” territory. Although other peregrines have clearly demonstrated this type of behavior, Elizabetha is different.
Now we have to figure out why she chooses to migrate over such a long period, in this case, fully a fourth of her year.
What could the advantages be for taking such a long time?
A slower rate of travel would allow her to become more familiar with her migratory route. She might be identifying and exploiting a new or previously reliable food source. She might be getting better at catching a particular prey species, e.g. parrots over a tropical forest canopy. She might simply be resting or replenishing her weight for the rest of the migration. Or, as our friend and colleague, Clayton White, suggests, she may just be taking longer as she gets older.
So here we have a remarkable adult female peregrine, Elizabetha, who not only showed us a new record for migratory distances over a single day (954 miles) but also the longest reported migration period on record for this species (94 days). Quite a contrast.