I have to report on two biological flights that were made in 1947 The first, Rockall flight, lasted about 9 1/4 hours on 30 July 1947, based on Stranraer. The second, Seal flight, was based on Calshot and Alness, and its duration was as follows: 27 September . . 1 1/4 hours 28 September . . 5 1/4 hours 29 September . . 9 1/2 hours 30 September . about 8 hours Both flights were in flying-boats and on the first six observers, and on the second nine or ten observers, were carried. 7 The objects of the Rockall flight were ( a ) to observe the status of birds on Rockall and take photographs of it ; ( b ) to observe the dis/ tribution of birds on St Kilda and North Rona and their adjoining islands, and to take photographs of them ; and ( c ) to search the coast on the west side of the Outer Hebrides and some of the Inner Hebrides for sea bird colonies and to take photographs of this coast. A ll objectives were secured. A paper is shortly to be published in British Birds , on the birds of Rockall up to date, showing that it is certain that guillemots did not successfully rear young in 1947, and that they are the only species of bird which ever attempts to nest upon Rockall. Aerial photography and observation has now shown that it is highly likely that a small number of guillemots lay eggs every year on Rockall but that these are washed off the rock by gales and swells before they can successfully hatch.