The population dynamics of Newfoundland caribou

The p o p u l a t i o n dynamics o f caribou (Rangifer tarandus) on the I s l a n d of Newfoundland were s t u d i e d 1957 to 1967. Four herds were recognized and censused: the Northern P e n i n s u l a — 450 animals i n 1958 and 400 i n 1966, the Avalon P e n i n s u l a — 125 i n 1957 and 720 In 1967., the'. Humber Ri v e r — 130 i n 1956 and 115 i n 1964, and the I n t e r i o r -4600 i n 1957 and 6200 animals i n 1966. The I s l a n d p o p u l a t i o n 1900-1910 was estimated at 40,000 animals. A f t e r 1915 these herds r a p i d l y d e c l i n e d and reached a low of perhaps only 2000 animals by 1930. The annual r a t e of increase Cr) of a l l the herds was low. The' Humber and Northern Peninsula herds showed no increase while the I n t e r i o r Herd grew at only 0.044. The Avalon Peninsula Herd showed the great e s t r a t e o f i n c r e a s e 1961 t o 1967, r= 0.120. The p o t e n t i a l r of Newfoundland carib o u i s probably greater than 0.30. A herd of carib o u introduced t o Brunette I s l a n d increased at r=0.352, from 17 t o 100 animals i n 5 years. In the I n t e r i o r Herd, b i r t h r a t e s were high and constant and averaged 0.85 c a l f per doe 2-years-of-age and o l d e r and 0.94 c a l f per doe 3 years and o l d e r . N a t u r a l m o r t a l i t y r a t e s were low beyond 6-months-of-age. They were 4 per cent f o r does, y e a r l i n g s , and calves and 9 per cent f o r stags 2-years-of-age and o l d e r . The k i l l of stags by hunters was 11 per cent and reduced the p r o p o r t i o n of stags i n the po p u l a t i o n . The s u r v i v a l of calves t o 6-months-of-age was s t r o n g l y c o r r e l a t e d w i t h growth of populations and appeared the main i n f l u e n c e on numbers ( c o r r e l a t i o n c o e f f i c i e n t r=0.922, P<0.01). The m o r t a l i t y of calves i n the f i r s t summer was h i g h ; an average of 69 per cent died i n the I n t e r i o r Herd and i n the Avalon Pe n i n s u l a Herd 30 per cent of the calves d i e d .