vi LETTERS TO MARCO 35 



butterfly. I say as he enters the arch, for 

 when he shoots out again his tail is closed 

 and the speed and suddenness of the exit 

 almost defies observation. This tropical 

 beauty is not surprising, as I believe swallows 

 are related to the sun-birds and humming- 

 birds, and the wonder to me is that they should 

 ever leave the warmer and sunnier latitudes 

 to return to the dark holes and corners where 

 they build their nests, with such a fitful 

 climate as we enjoy in England. 



The river is in high flood, and should it 

 rise much more the swallows will be unable 

 to reach their nests, as the entrance archway 

 will be closed up. Yesterday the weather 

 was wild, with a driving rain and northerly 

 wind all day long ; but it was, in an ornitho- 

 logical way, most interesting, as we were 

 visited by a large flock of what I believe were 

 terns, possibly they were black-headed gulls, 

 but I am nearly sure they were terns. My 

 only book on birds is Bewick, and his account 

 of either bird is very meagre ; but in the 



