I was back birding in the Rainwater Basin on Saturday (18 July). The most surprising find of the day was the discovery of two Double-crested Cormorant pairs with nests at a large wetland. The nests appeared to be mostly completed. One bird, though, was observed bringing sticks to its nest and the females on both nests were not fixated on nest contents. Thus, I suspect no one has laid any eggs yet. This observation represents the first known nesting by this species in the Rainwater Basin. And, yes, Neotropic Cormorant was initially considered since that species has nested at Cheyenne Bottoms in Kansas, but it was subsequently eliminated as a possibility after a little bit of scrutiny.
Frankly, this is a species I never expected would be found nesting in the Rainwater Basin since Double-crested Cormorants primarily eat fish. Rainwater Basin wetlands are shallow and water levels fluctuate widely from season to season and from year to year. They frequently dry up completely. Thus, they do not typically support any sort of fish population.
However, Double-crested Cormorants are opportunistic feeders. At this particular wetland there appears to be an irruption (sudden increase in population) of chorus frogs. The frog density I observed on Saurday was as high as I ever recall seeing anywhere. I captured a few seconds of video of all the frogs along the wetland edge. It can be viewed, below.
The future will tell if these Double-crested Cormorants are serious about nesting or are just messing around. Shorebird migration also is picking up, which is expected this time of year. Best shorebirds of the day included Marbled Godwit, Black-necked Stilt (2), Western Sandpiper (2) and Short-billed Dowitcher (2, one of which is pictured, below).