Voyage from Liverpool to Boston - Off South Coast of Ireland.
1911.
August 2
No 10
[August 2, 1911]

Remarkable flight of Gulls.
Lesser Black-backs glide against wind as well as Herring Gulls.
Relative positions of wings & body in gliding birds

hour these birds accompanied the Herring Gulls mingling with
and keeping pace with those on a level with our upper deck but
flying all the while as Gulls fly on ordinary occasions that is
by alternate flapping and sailing, the wings being beaten vigorously
every few yards. Quite evidently these big Black-back[s] were unable
to glide far against the wind on motionless pinions else they
would surely have practised it. Yet two adult Lesser Black Backs
(L. fuscus) were no less skillfull at it than the Herring Gulls every
one of which could and did do it. Indeed, with the exception
of the two L. marinus, all the Gulls in the flock were frequently
gliding at one time sometimes for hundreds of yards without
a single wing beat on the part of any of them.
  While thus engaged at the height of the blow their wings
were, as I have said, not only strongly crooked and much incurved
but also held much further back than common so that a larger
portion of the body was shown in advance of where the wing