78 JOHS. ANDERSEN 



Without collar 122, blue 154 (45 per cent of those marked), white 

 + green-red 186 (55 per cent of those marked), (total marked 340). 



Thus old and young individuals were observed in almost the same ratio 

 as the corresponding marks were present in the herd. 



On applying the Lincoln Index (p = anjr, where a = number released; 

 n = number observed; and r = number of marked among those observed, 

 the three figures being 74, 462, and 340 respectively) one arrives atp = 100 -6 

 with a standard deviation of 2-8 {\/a^ n (ti — r)jr^), a result which points 

 to a spring population of 100 db 1 {^' S X s). 



More comphcated methods of calculation, like that of Bailey (1952) give 

 exactly the same result (p = lOO- 5; 5 = 2- 8). When the population estimate 

 is based on observations made during the first month after the trapping (i.e. 

 two-thirds of the observation period) the same estimate is obtained although 

 the standard deviation increases. 



Thus there is reason for beheving that the spring population consisted of 

 approximately 100 deer. In order to compare with the 1950 data it is neces- 

 sary to add fifteen deer (removed from the herd during trapping) and six 

 (killed during the autumn) ; according to this the autumn population must 

 have been about 120 deer in this wood which in 1950 was found to hold 117 

 deer. We are of opinion that the close agreement indicates that this popula- 

 tion is near the carrying capacity of the wood. 



Proceeding in the same way we have made another estimate based on the 

 thirty-three deer captured, marked and released in 1956; the calculations led 

 to a population estimate of 100-120 deer. 



What about emigration and immigration during the trapping and observa- 

 tion periods? We have reason to believe that during autumn and winter 

 migrations take place to a very limited extent: the marked deer are easy to 

 spot, all forest owners and sportsmen in the neighbourhood know of our 

 experiments and inform us whenever they see anything relevant, further- 

 more we pay a reward of approximately 25/- to sportsmen who hand in a 

 collar. Emigration has only been noticed during the summer, at which time 

 it is considerable. This aspect of our experiments (partly based on the marking 

 of newly-born fawns during the summer) will not be discussed further here. 



Returning now to the population estimate from 1958 I would like to say 

 that there is a limit to the number of colour combinations that can be used 

 during a sequence of years. It may therefore be of some interest to mention 

 how a single category of individuals, such as fawns, can be used every year — 

 there are several reasons for marking the fawns differently from other age- 

 classes. 



In 1958 we released thirty-two 'blue' fawns, constituting about one-third 

 of all deer present in the wood. By focusing attention on those thirty-two 



