96 U. S. NATIONAL MUSEUM BULLETIN 217 



in 1950 and 1951, but no dipper was reported. Raymond Paneak saw 

 two dippers there in April 1953. At the head of the Savioyuk River 

 near open water and just within the northern limit of spruce forest, 

 Rausch recorded an observation of a dipper on October 10, 1950. 

 Four were reported from Savioyuk on February 10, 1951, by Simon 

 Paneak. 



Two dippers were seen by Robert Paneak at Naniksruk Springs, 

 a winter fishing place, some 40 miles north of Tuluak Lake, on March 

 31, 1951. One was seen on Kanayat Creek by Elijah Kakena on April 

 9, 1951. 



Where the waters are unfrozen a dull cloud of ice fog called "water 

 smoke" may be seen for a long distance rising in the still winter air. 

 These places of open water are called springs by the Nunamiut. They 

 provide fishermen with access to water in winter, and they are there- 

 fore carefully examined and well known. In a stretch of about 100 

 miles south to north on the upper John and Anaktuvuk Rivers, 

 dippers have been reported in four places during winter. In the 

 country within 15 miles of that line there are three or four 

 other places which might be suitable, making places for about 6 or 8 

 pairs of these small birds in about 3,000 square miles of arctic moun- 

 tains which are otherwise completely snow and ice bound for eight 

 months of the year. 



Some of these open water locations are only a few yards in extent, 

 and there are so few of them that individuals or pairs are often sepa- 

 rated from each other during more than 6 months by 30 or 40 miles 

 of frozen country completely unsuited for a dipper's sustenance. 

 Territories vacated by death are nevertheless filled, so that in spite 

 of the winter isolation of its members and their usual close restriction 

 to a minute feeding territory, the population tenaciously retains the 

 integrity necessary to preserve its small numbers. 



The population density of dippers in northern Alaska is probably 

 the least of any small bird in the north, and it may be suggested that 

 the individuals and pairs live in isolation from their kind unique 

 among animal populations. 



Our scant physiological knowledge indicates hypothetical diffi- 

 culties for so small a bird feeding under water in arctic winter condi- 

 tions. But the individuals show no signs of strain and are undoubtedly 

 adapted so that their lives are passed without continuing physiological 

 stress. Their social scheme must also present a fine adaptation to 

 their isolation in order to preserve the coherence of this remarkable 

 population of widely separated families. 



