THE PETREL. 21 



The bird which approaches the nearest to the bank- 

 swallow in its manner of breeding is the stormy pe- 

 trel (Thalassidroma pelagica, VIGORS), the storm- 

 swallow of the Dutch, whose great power of wing 

 enables it to sweep over the ocean at every distance 

 from land, and even to weather the most tempestu- 

 ous winds, while with its webbed feet and light form 

 it can actually walk upon the billows with as much 

 ease as a sparrow can hop along a garden walk. 

 " It is, indeed, an interesting sight," says Wilson, 

 "to observe these little birds, in a gale, coursing 

 over the waves, down the declivities, and up the 

 ascents of the foaming surf that threatens to burst 

 over their heads, sweeping along the hollow troughs 

 of the sea as in a sheltered valley, and again mount- 

 ing with the rising billow, and jus-t above its surface, 

 occasionally dropping their feet, which, striking the 

 water, throw them up again with additional force, 

 sometimes leaping, with both legs parallel, on the 

 surface of the roughest waves for several yards at 

 a time. Meanwhile they continue coursing from 

 side to side of the ship's wake, making excursions 

 far and wide to the right and to the left, now a great 

 way ahead, and now shooting astern for several hun- 

 dred yards, returning again to the ship as if she were 

 all the while stationary, though perhaps running at 

 the rate of ten knots an hour. But the most singu- 

 lar peculiarity of this bird is its faculty of standing, 

 and even running on the surface of the water, which 

 it performs with apparent facility. When any grea- 

 sy matter is thrown overboard, these birds instantly 

 collect around it, facing to windward, with their 

 long wings expanded and their webbed feet patting 

 the water. The lightness of their bodies, and the 

 action of the wind on their wings, enable them with 

 ease to assume this position. In calm weather they 

 perform the same manoeuvre by keeping their wings 

 just so much in action as to prevent their feet from 

 sinking below the surface."* 



* American Ornithology, vii., 97. 



