River, 49 miles SE of Umiat. It seems likely that the striking improve- 
ment of homing speed could be due tc familiarity with the terrain, since 
the species of bird used is one found in heavy migrations through the 
valley of this river. Another experiment seemed to prove the same point. 
A few miles north of Umiat, the tundra changes from a dry, rolling, 
prairie-like terrain to a flat area broken by lakes andponds sonumerous 
and so similar in shape that pilots find the terrain extremely difficult 
for contact flying. So, apparently do the plovers; for three of them, re- 
leased 33 and 48 miles NW of Umiat inthis area took 10, 21 and 35 hours 
to return. The ten-hour flight was made on the only clear day when the 
snowcapped Brooks range would have been visible. 
Despite the numerical inadequacies of the experiment and some 
possible complications caused by poor visibility, it suggests that homing 
by birds which nest in the Arctic is not much different from that dis- 
played by many species studied in temperate latitudes. The question 
deserves a more conclusive answer based upon extensive experiments. 
In addition to the evidence that birds have a well developed visual 
memory, it is important to realize how wide-ranging are many of the 
larger species. This was brought to our attention in striking fashion 
during the summer of 1948 when we made flights over much of the Arctic 
looking for nesting birds for homing experiments. We noted one flock 
of snow geese which were not migrating but were merely cruising along 
the coast in search of food or nesting sites. From observing them at 
various points, we concluded that they had covered 120 miles in four 
hours or less. When we allow for the age which ducks, geese, and other 
large birds are known to attain, 
Wee e led it iseasy to imagine that in a few 
1°) years they become familiar with 
a great expanse of territory. 
(Sse eS 
100 mies 
Yet visual landmarks can 
hardly explain the migratory 
flights of young birds not guided 
by adults. We have some rather 
interesting evidence on these mi- 
- grations. Several weeks after all 
the adult wild crows from a cer- 
tain section of Alberta had mi- 
grated southeast to their winter 
\ range (known from recoveries of 
ae banded birds) Rowan (1946) re- 
Numbers in circles leased some young crows. Thein- 
Hee cone normal mgration tensive local publicity accom- 
a eceoeey, Beg Shad panying the: release resulted in 
severalreports and recoveries of 
-the young birds at the points in- 
dicated in Figure 5. The number 
within each circle represents days 
elapsed between release and cap- 
Figure 5. Map of experiment per- aS, . 
folmea by Rewari Which shows he ture. In a similar Seta A 
young crows could migrate in the performed FEA SRS ago with 
correct general direction evenafter White storks the young birds flew 
being held incaptivity uitilalladults in directions roughly equivalent 
of species had migrated southeast. to their normal migration but 
Argue 
