By Susan Heath
Well as usual the weather is playing havoc with our field work this winter. We missed both of the last two Mondays, one to fog and one to wind. There are three nests that we can see from shore though so we were able to do some of our observational work on those. Amanda is doing Time Activity Budgets (TABs) on all the nesting birds. These are 20 minute observation periods where we record the behavior of each adult every 15 seconds. We do them three times during incubation and then again three more times during chick rearing. The purpose of this is to assess whether Laughing Gulls negatively affect adult oystercatchers during nesting. We are pretty sure they do but it takes statistics to back that up thus the TABs. It’s been really interesting watching the birds like this and we are learning a lot about their behavior. The oystercatcher adults will chase away the Laughing Gulls, but they also get very upset if a Great Blue Heron or Ruddy Turnstone comes near their nest. The Great Blue Heron makes sense – they could take an egg or chick easily but Ruddy Turnstones? Someone told me or maybe Amanda read that Ruddy Turnstones are big egg predators. Interesting. Who knew? Well, the oystercatchers knew I guess! We also observed Forster’s Terns and Laughing Gulls trying to steal the food that the adult oystercatchers brought back for their chicks. Naughty, naughty!
In week three our dedicated volunteers (Paula Kennedy and Stennie Meadours) at the Texas City Prairie Preserve (TCPP) found two more nests. One of these pairs (P5 & P6) has been together since the start of our study and has remained on the same territory. In 2011 they fledged three chicks so I think they have one of those prime territories that is worth keeping. The other nest belongs to M0 & K4. M0 has remained on the same territory since we began our study and was previously paired with an unbanded female. We have no idea what happened to her, but from the very beginning she was a little odd and we always referred to them as M0 and his crazy wife. That’s a story for another time though. M0’s new mate K4 was previously paired with an unbanded male on a nearby territory but they were never able to fledge a chick because their territory was too low and their nests always overwashed. M0, on the other hand, fledged a chick in both 2011 and 2012 so K4 has clearly moved up on the territory scale by abandoning her former mate and pairing with M0.
The two additional nests at TCPP make eight nests in February. That many nests so early is unprecedented. We always found one or two but never eight. It’s going to be interesting to see how many of them make it. As I said before, statistics have shown that the early nests have the best chance of surviving.
In week four, because of the bad weather day we had one day in Bastrop and Drum Bay (Thursday) and one day in West Galveston Bay (Friday). Nothing much is happening in Bastrop and Drum Bays yet. The pairs were all hanging out on their islands last Thursday though instead of out wandering around so it seems they are getting ready. The most exciting thing that happened that day was our boat died and we had to call in the USFWS to come rescue us. I can’t thank you enough Lee Hoy and Jeff Frasier!
This past Friday on our West Galveston Bay run, we found six new nests and most of them had a full clutch (3 eggs). That means the oystercatchers were laying eggs right after we had a very strong cold front that caused near freezing temperatures for three or four nights in a row. These are some tough birds. Paula and Stennie also found two more nests at TCPP so we now have 16 active nests. Except…… drum roll please…… the first nest we found, the one from February 10, apparently hatched because the eggs were gone when we checked on Friday. Of course there is more than one reason why the eggs could be gone. A predator could have gotten them, but I don’t think that’s the case this time. This was the first pair to fledge a chick last year and we almost didn’t realize they had a chick because they did not act defensive when we were around their nesting territory. Typically, when adult oystercatchers have chicks, they go nuts when you get around their nesting territory. They fly around calling and cussing you out and warning the chicks to stay hidden, which the chicks do very well. Here’s a photo of two chicks hiding.
Because of the adult behavior, you can usually tell if the nest hatched or failed. But not K6 & JA. They stand around as if nothing at all is going on and then suddenly you notice they have a nearly fledged chick! That’s what happened last year. So anyway, I feel pretty sure they have some chicks. We looked around briefly but couldn’t find them. The chicks are really vulnerable at that stage so we don’t hang around long trying to find them. We tried to spy on them from afar but they were having none of that and we saw nothing but two adults acting as nonchalant as ever. So we didn’t see the chicks but if we had they would probably have looked something like this.
Stay tuned for actual photos of these chicks!
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