The Oystercatcher Diaries 2014: Weeks 1 and 2

By Susan Heath

Our 2014 field season officially started on Monday, February 10 and we found a nest in West Galveston Bay that very first day! This pair (K6 and JA) nested very early last year as well and we completely missed their nest because we weren’t looking early enough. We were ready for them this year. Here’s a picture of their nest.

They nest on an island called Struve Luci which is just off the shore of Galveston Island. There are three other pairs of oystercatchers on this island and that same day we found that two of the others had nest scrapes, an indication that they were getting ready to lay eggs. Sure enough on Friday we found that both of them had begun to lay their eggs. L9 & L8 had laid two eggs and 12 & unbanded had laid one egg. A full clutch for oystercatchers is three eggs so we expected that they would lay more. On Monday (the 17^th) we checked on them again and found that each now had three eggs. All three of these pairs are now incubating their nests. Do I need to remind you that it is February?! Here’s a photo showing where L9 & L8’s nest is located. Oystercatchers almost always situate their nest close to some low vegetation like this one is.

There are lots of reasons why it is a good idea for this species to begin nesting this early even though it is still cold and our research has shown that statistically the pairs that start the earliest have the highest productivity. As the season wears on, productivity slowly decreases and the latest pairs to lay eggs (June) rarely fledge a chick. Two of the biggest problems that nesting oystercatchers face are predation of eggs and small chicks by Laughing Gulls and overwash from high tides. Laughing Gull numbers don’t start building until late March and April when they begin nesting though so the chicks resulting from oystercatcher nests laid in February are too big to predate by the time there are a lot of Laughing Gull around. As for overwash, on the Gulf Coast our tides are mainly wind driven with strong north winds causing very low tides and strong south winds causing very high tides. In winter the constant string of cold fronts bring north winds so there isn’t much chance for a nest to overwash. Later in the season when the cold fronts die down or aren’t very strong, the south winds build up causing nests to overwash, chicks to be washed away, or chicks to starve to death because the adults can’t find enough food to feed them. In the summer a tropical storm almost certainly means very high tides and the end of any oystercatcher nesting activity. Here’s a banded chick that likely starved to death in 2011.

While some pairs are already nesting, others haven’t returned to their nesting territories from their winter wanderings so we aren’t quite sure yet how many pairs are present at our field sites. These are West Galveston Bay, Swan Lake, Bastrop Bay, and Drum Bay. We have volunteers monitoring nests at the Texas City Prairie Preserve on Dickinson Bay as well. This year for the first time, there are birds that we banded as chicks (2011) that are old enough to breed. We have found five or six of them already paired up with mates which is very exciting. I’m anxious to see how they do as I have suspected for a while that the older pairs with a lot of nesting experience fare better than the younger pairs. Time will tell. I will try to make an entry to the blog once a week to keep everyone updated on how the oystercatchers are doing this year.

Remember, GCBO is a non-profit. We don’t receive any funding from federal or state agencies unless we are awarded a grant from them. The majority of our grants require matching funds and our oystercatcher grant from the National Fish and Wildlife Foundation requires a 1:1 match which means for every dollar they give us, we have to raise a dollar from another source to match it. Any donation no matter how small will help us meet that requirement!