I’ve been looking forward to putting this post together since I took these photos on the first day of fall this year. I just love it when all the tumblers fall in place and I capture an interaction that tells a story. I was camped out along the banks of Elm Lake at Brazos Bend State Park watching Purple Gallinules methodically turning over what seemed like each and every lotus leaf in their paths. Grab; step; fold; hold. Grab; step; fold; hold. Again and again, they applied the technique as they criss-crossed back and forth across the carpet of lotus leaves. I assumed they were hunting but, for what? Strangely enough they ignored the aquatic snails conspicuously stuck to the undersides of the overturned lily pads. The snails looked pretty good to me, and snails are on the typical Purple Gallinule menu – along with seeds, insects, crustaceans, fish, eggs, and marsh bird nestlings (!) – but they passed on the snails. Not even a “no thank you” helping. It wasn’t until I was able to look at my photos closely that I was able to identify the special of the day – aquatic leaf beetles.
Over a period of about an hour and a half, I captured 17 unique predator-prey interactions and nine of those involved Donacia, the aquatic leaf beetle. Two involved fish and the remaining four menu items – unidentified. This juvenile Purple Gallinule found its beetles either sandwiched between overlapping lotus leaves or nestled within enrolled emergent lotus leaves. I also saw the gallinule peek inside the rolled up leaves presumably checking for beetles before ripping a small hole in the side to extract the snack. (I’ll post that series later.)
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