PhD student Jesse Conklin, from Massey University, explains how you can tell when godwits are getting ready to migrate. He talks about their preflight behaviour, and you can hear the calls they make as they round each other up to go.
Most of the time godwits are basically silent in the non-breeding season. They will do a couple of little chatter calls, or when they are flushed by a hawk, they might give an alarm call, but in general, they don’t do a lot of vocalising. But during the breeding season, they are very vocal. They have a whole range of vocalisations that are specific to behaviours that they are doing in Alaska in the nesting season, and you start to hear some of those late in the season here in New Zealand.
So maybe late February, I’ll start hearing calls here and there that remind me of Alaska, what the birds are going to sound like. They give some of these calls very energetically when they are thinking of migrating, and it seems to be a “I’m ready to migrate, who’s with me?” kind of thing. It’s a really piercing high-pitched two-note call they mostly give, and if you are downwind, you can hear it from hundreds of metres away.
So I can stand on the downwind side of the estuary and listen for this call, and it’s kind of a ‘cahh, cahh’. It’s basically birds telling each other that they are thinking about migrating. Sometimes, over a period of half an hour or sometimes 5 hours, that bird will fly around the estuary making this call and picking up taggers-on. You’ll get this group of birds, and they are sort of egging each other on to go.
They will often do a lot of preening and bathing as well and wing stretching. First, they are going to leap off the mudflat and not set their legs down again for 7 days, and they are going to be flapping the whole time, so they want to do a lot of stretching and sort of exercising and making their feathers as nice and tidy as they can before they go.