Too many times we are on an 'Audubon walk' or a 'field trip' or just a casual walk-about...with nothing in particular in mind for we are out to see what we can see. But next time, take this challenge.....go out and with no pretense in mind, find one species and dwell on that species only. Learn from it, observe it. I was just doing the usual this past walk-about....out looking for any-old bird and came across a Gull-Billed Tern (Originally called Marsh Tern by Bent in 1921). I decided to focus on this one bird and ended up with a few shots yet more importantly; questions. Slow down I tell myself......observe nature, watch wildlife., question nature...always question...brave the gnats and flies and while they are quite content on forming a bug halo around your head, just give them no bother. Take the time to observe. Slow down time, forget what else is to be had.....observe.
Now...this Gull-billed Tern is found on all continents with the exception of our southern snow exposures one. This Tern differs in that while they have a preference for salt water marshes and habitat similar to other Terns, these Terns do not dive into the water but rather prefer mudflats for their food source. Look at the close-up shots below which merely mirrors the full sized ones above....the left one has the Tern fully placing it's beak into the sand. You have to turn your head to grasp this view. The black portion is the cap/top of the Tern's head with beak encased in the sand. The second shot on the right has lead to 'success' as a crab has been plucked from the mudflat.
I can see if the mudskipper or small crab is a top the mud as eye sight would come into play. But how does it know when 'the same' is below the mudflat line and hidden from sight? I have no idea and research does not offer any help nor does it address that issue. Past research will look at how Gull-Billed Terns might steal food from Common Terns (Sibley, 2000), or swoops down to pick small crabs, spiders, and even larger prey such as lizards (Parnell, 1995) from the mudflat, but no one addresses how they can determine food which is buried within the sand as evident by the the images included in this blog. A complete enigma as I stated a bit earlier.