FUR-SEAL CENSUS, PRIBILOF ISLANDS, 1918. 125 
SURPLUS BULLS. 
No count of bachelors on the hauling grounds was made at the 
height of the season because of the interference this would have 
caused in the killings.then taking place. In its stead the surplus 
bulls were counted about the back of the rookeries. This class 
includes those males found here and likewise those which are on the 
hauling grounds and.elsewhere; obviously, the last must be estimated. 
No counts of them are possible. A count about the rookeries, 
however, is valuable because in a way it shows a breeding reserve 
which is unquestionably known to be in existence. For this purpose 
they aethite added to the idle bulls but would tend to give an 
erroneous impression, because the count only represents a very small 
fraction of the number in actual existence. If those counted were 
added to the number of idle bulls they would make 2,444 +3,951, or 
6,395 nonbreeding males found about the rookeries at the time of the 
1918 height of season harem count. This makes the percentage of 
idle and surplus bulls to harem bulls 119.66. From this it is apparent 
why the average harem was at or very near a minimum. 
SurpeLus Butts Countep 1n 1918. 
Rookery. cue Rookery. pie 
ST. PAUL ISLAND. ST. GEORGE ISLAND. 
UIC OW ies SASS See So oe re aes eee GOMIPNGrinben ncn Sec a0 Ste olns tenes asacseee 91 
ATS oe 2 Bee aa eee nee. OG" 'Starayarartil: 223. ek oe 56 
CPeTy OLE) Ree ee Bree ees LGStASMAdMS s..ca asec ope ese eet eee 29 
LE 71S) ua 20 Se ih aS Se HGoal OMA ceca ceca sc test eas Sklcslcsee eS 
PiveliCh stweee ok alec. gos ee tone Seen PANG Sc 1 4: | a ee Se ee eee See 37 
el GY Spa) bale OS SR Ie ete a 267 
Sithelunpas:=ceL le see 8 sosse ELS 93 Weta: 32084 Son oe ok 217 
BAR eee ee ret enn soos ne eee 500 == 
Pipe Zapadni. - oss .1 2 ot ct Bee 54 Total, bothislands. 2. 222--4.2--2: 3,951 
LEG NAD pe Steg se Scere he ae Cin de 194 
Pathe Polovina. 1.037. 12 se ae 80 
Cy ON Coon See ee SeRSE SE Er pAmOSsercriecis 157 
MOStOCHI See scott esi ee Seces ceeeeens Se 1, 260 
(0) 2) (pee Pere ae onoeee eee 3, 734 
GAINS OF BULLS. 
The great significant fact standing out in the census work of 1918 
is the percentage of gain of harem bulls. This was 10.18 for the 
entire herd, a figure differing but slightly from the increase of the 
cows. Since there was an overabundance of idle and surplus bulls, 
it seems to show conclusively that the average harem in these two 
years was at its minimum. ‘The average increase of harem bulls the 
five preceding years was 36.68 per cent. The increase or decrease of 
idle bulls means but little at this time. The difficulties of deter- 
mining the actual number in this class as distinct from surplus bulls 
are almost insurmountable. Those animals at the rear of the rookery 
which might properly be called idle bulls either merge into the haul- 
ing grounds on one side occupied solely by surplus bulls and bach- 
elors, or on the other side into the group properly known as idle bulls. 
It would not be right to call all bulls on the hauling grounds ‘“‘idle 
bulls.” Neither could the figure obtained from counting surplus 
bulls on the back of a rookery be considered to represent all the 
animals in this group. The great difficulty lies in the fact that im a 
large number of cases there is no line of demarcation between a 
rookery and a hauling ground. The rearward extension of the breed- 
ing seals is bordered by a sharp line, but the other classes are not. 
160695°—20 25 
