Least Bittern
Botaurus exilis
Content and photos by James Giroux
Although fairly common, the Least Bittern is not always easy to find. Like its cousin, the American Bittern, the Least is well camouflaged, and usually remains motionless when being watched. This can make it very difficult to spot among the reeds where it hangs out. Its small size – compared to other herons – compounds this problem.
As birdwatchers, we tend to overestimate the size of all birds, because almost all of our encounters are through the magnification of binoculars or a scope. We are often amazed at how small they are, when for instance, we encounter a dead bird, or get to hold a bird at a banding event. If you have seen a Least Bittern, close your eyes right now, and estimate its length and weight. Also, take a guess at how narrow a gap one of these birds can walk through. The gap between two upright books for instance.
The length of the Least Bittern ranges from 11-14 inches, the weight from 1.6 to 3.4 ounces! If your guess was below 4 ounces, then kudos to you. How about the gap they can walk through? John James Audubon documented a captive bird walking through a 1.5 inch gap between two books. The birds are narrow to begin with at 2.25 inches across, but they can squeeze themselves to fit between the narrow reeds they encounter in their habitat.
Least Bitterns are in the heron family, and for most herons you cannot tell males and females apart. Not so with adult Least Bitterns. The male sports a black cap and back, while the corresponding female parts are a medium brown. See photos below.
Least Bittern male – McFaddin NWR, April
Least Bittern female – Sea Rim State Park, April
Least Bitterns hunt and eat in typical heron fashion, walking slowly and quietly looking for prey. Their diet consists of insects, crustaceans, fish, amphibians and reptiles. They are very solitary creatures, and you will almost never see more than one at a time. I was lucky enough to be in the right place at the right time with my camera ready when the bird below came around a corner.
Least Bittern female – Sea Rim State Park, April
As the range map below shows, Texas has year-round residents in the south and along the coast. A large population inhabits the eastern U.S. during breeding season, but heads to Central America in the winter.
You can’t tell it from the range map, but Least Bitterns are rare in Austin. There are only two records from Hornsby Bend (1994 and 2017). There are no records at Southwest Greenway. So, if you are looking for this bird, you should head down to the coast. Sea Rim State Park and McFaddin NWR are great places to look. I found the rather tame bird below on the boardwalk at Sea Rim giving me the “eye”.
Sea Rim State Park, April
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