SHORT COMMUNICATIONS 
159 
Momia 
'• English Channel area. Tule Lake Refuge 
lia 
aggression (McAllister 1958. Cullen et al. 
these occurrences are not included. My 
J^ives in this paper are to provide a lull 
option of pattering and pattering flights by 
r numbers of grebes, and to discuss possible 
l< **s for their occurrences. 
RESULTS 
Nervations in ihe southern English C hannel 
-5 May started at 0900 hrs. Over 200 Eared 
hes were scattered partially in loose groups all 
r 'he EW pan of the English Channel around 
d ay when about three quarters ot them 
aged in pattering. The grebes did so m 
Secutive waves, all into a western direction 
the connection to the NS canal. The 
den take-off by one or two grebes seemed to 
* others in their immediate vicinity and on 
their way to move in the same direction. Groups 
of 10-30 birds pattered over a short distance (20— 
30 ml. some briefly loosing contact with the water 
surface in a pattering flight. Grebes getting briefly 
airborne possibly did so to avoid collision with 
conspecifics that remained stationary on the water 
surface. Grebes landed ahead of others that started 
similar maneuvers in their wake, perhaps cairying 
along some of those that had just stopped 
pattering. A few additional waves of pattering 
were launched. Some birds dived after landing; 
others elevated their necks, remained alert, and 
looked around without changing their westward 
orientation. Most of the population, including 
subgroups closer to the NS canal which were not 
observed to patter, was swimming in the direction 
of the NS canal. The eastern and central parts ot 
the EW canal were rather empty of Eared Grebes 
after some 2-3 min. leaving only a few Western 
(Aechmoplwrus occidental !*) and Clark s grebes 
(A. clarkii) and a few ducks remaining. Fewer 
than 100 Eared Grebes were still swimming in the 
western part of the EW canal towards the 
connection with the NS canal when they encoun¬ 
tered about 40 birds swimming in a group to re¬ 
enter the EW canal. A rough count less than 
10 min laler indicated that >200 Eared Grebes 
had again spread over this canal. 
Pattering and pattering flights started anew only 
Jo min after the start of the t.rst genera 
movement by the Eared Grebes. Take-off by one 
o r two Eared Grebes incited others m then 
surroundings to join as before. The buds moved 
westward in several waves and continued sw.^ 
mine into the same direction after landing, 
grebes left the EW canal where only about 30 
remained, all towards Us western t ,1 A fe 
group of swimming grebes returned - I > at ® . 
a" lot^eTperiocf without graup pattering, but 
with continuous calling, occasional disp ays and 
much surface feeding on phantom midg^ (C/^ 
Zrus ciystiMinis) followed until -1400 hrs 
Individual grebes performed feeding dives, but 
no group diving, or submerging and surfacing 
near unison was observed. The general patlenng 
in waves and westward swimming towards the 
connection with the NS canal started again and 
most Eared Grebes finally left the EW canal. The 
first grebes had turned and swam to return to the 
EW canal when a sudden simultaneous eastward 
