Friday, August 14, 2009

Alaska - the contrasts

One skinny godwit, Alaska
For my final reflection on our recent work in Alaska I can't help but marvel at how godwits have to adapt so quickly to such radically different habitats, the tundra being so different from the inter-tidal flat in New Zealand. These contrasts struck us regularly:

- the wide open grassey tundra, miles from the coast, compared to the sandy/muddy inter-tidal flats and the obvious associated change in diet. The birds we saw were mostly eating berries, compared to polycheate worms and other invertebrates in NZ.

Australian bird (orange flag) eating berries in Alaska.

- feeding is determined by tide cycles in New Zealand, birds getting to feed on low tides, yet in Alaska feeding depended, at least for breeding pairs while we were there, on being able to get off the nest. We went with assumption of 12hr shifts, though we had no strong evidence of this. Other failed breeders of course could eat as they wanted.

- birds in NZ congregate together, whereas on the tundra they were largely isolated pairs, possibly kilometers from the nearest godwit. Failed breeding birds did start congregating towards the end of our stay however.
- they shift from NZ cycles of night and day, to 24 hours daylight
- birds had to deal with entirely different species around them, long-tailed jaegers contrast massively to knots, gulls and other birds from NZ. Godwits would be regularly seen beign chased by, or chasing jaegers. One thing that surprised us though was how the majority of godwit nests we encountered were in close proximity to a jaeger nest!
Overall, no matter how you look at it, you can't help but marvel at these amazing birds. Not only for their staggering migrations, but also for how they can cope so well in such contrasting environments.

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