DARKEST-EYED LAND VERTEBRATES

 

  

 I can imagine asking my young friend John to characterize this group of eight families and getting an answer something like this, “ Sir, they are very mobile. Sandpipers may see more of the world on their migrations than any other birds - they travel thousands of miles. Some swifts may spend as long as a year without lighting. Swallows and sunbirds are  two passerine families that are very much like two non-passerine families in the list, swifts and hummingbirds. I would venture to say that swifts and hummingbirds are the most aerial of the non-passerines and swallows and sunbirds are perhaps the most aerial of the large families of passerines. All four families are very mobile. Terns are called “sea swallows.” All these animals are built for speed. Nightjars are similar except they fly at night. All are fast-flying. Some members of the weasel family are so fast that they are “flying” in a figurative sense. They are all very mobile, Sir, and that is a fact.”

 

Even though these dark-eyed families differ from each other in various ways, none are similar in behavior to the lightest-eyed families. In my view, the critical difference has to do with time or timing. All of the lightest-eyed families employ skilled waiting or delay of response. None of these darkest-eyed families do that. They use methods to obtain food in which waiting would be counter-productive. Skilled not-waiting is called for and all of these animals appear to employ to good effect immediate, quick reactions.