as described under "Methods." The mmbers of broods known to reside in only 
one pothole throughout their preflight development are included after the 
summaries for each species, 
Canvasback -- The first marked brood observed was that of a canvasback, 
colored green, hatched June 15 from a nest located in the small semipermanent 
cattail pothole southeast of No. 5. It was located the following day on 
pothole No. 5, where it remained until some time between June 26 and June 29. 
On the latter date it was seen on pothole No. 1 where it could be identified 
until July 7, which was the last time the color was observed, However, a 
brood which can safely be assumed to be this one remained there until July 12. 
On July 13 a thorough coverage of this pothole as well as all areas within 
oneshalf mile failed to reveal the brood and none that could possibly be this 
one was ever seen again, This brood was 27 days old (Class IZ) when last 
seen, and was still accompanied by the hen. The minimum distance traveled by 
this brood was 0.28 miles in 28 days, 
A second canvasback brood of three that had been dyed with Ponceau SX 
hatched on June 30 from a nest in a cattail clump at the north end of pothole 
No. 33. The brood remained on this pothole until July 14. In fact, on July 7 
after dark, they were actually found on the nest, where the hen was apparently 
brooding then, 
From the age of 2 to | weeks this brood was seen on four different 
potholes, finally returning on August 1 at the age of 32 days to the second 
one in which it had been observed, At this time the young were Class II and 
the color of the dye was last seen, They were observed on this pothole seven 
times between August 1 and the last visit on August 22. At this date (age, 
Sh. days) their flight feathers were almost fully developed and they appeared 
to be ready to fly. The minimum distance traveled overland by this breod was 
0.81 miles in 5) days. 
Eight unniarked canvasback broods were recognized in two or more potholes 
and their movements are outlined below. The dates listed show the first day 
a change in location was noted. In some cases broods were observed on 
intervening dates on the pothole last cited. 
1. A Class I brood of seven. June 17 - still on nest at Type Bl pothole 
south of No. 18, June 18 ~ on pothole No. 33 (not seen again). Travel - 0,18 
miles in 2 dayse 
2. A Class I brood of seven. June 17 = on pothole No. 36. June 26 = 
on pothole Noe 39. June 30 = on pothole No. 0 (last seen). Travel - 0.16 
miles in 13 days. 
3. <A Class II brood of six, June 26 = on pothole No. 36. July 1h ~ on 
‘ pothole No. 39. July 22 = the hen and five Class III young were on pothole 
No. 40, while one Class III young was on pothole No. 39. The hen ‘and the one 
lone duckling were last seen on this date. July 29 = brood last seen (ready 
to fly). Travel - 0.16 miles in 33 days. 
lh. A Class II brood of nine. July 1 - at pothole No. 22. July 5 - at> 
pothole No. 23. July 10 = at pothole No. 21 (last seen). Travel - 0.13 miles 
in 9 days. 
5, A Class I brood of one, July 1 ~ at pothole No. 33. July 22 = at 
pothole No. 35 (Class III). July 30 = young last seen (ready to fly). Travel - 
0.12 miles in 30 days. 
