Table 2. Summary of the demographic parameters (±SE) used for the post-breeding population model for razorbills breeding in Atlantic Canada, 1995–2008. Productivity is the mean number of young fledged per pair.
|
|
Parameter |
Gannet Islands |
Machias Seal Island |
Sources |
|
Population size (breeding pairs) |
9808 |
550 |
2,3 |
Juvenile survival (age 0–2) |
0.482±0.033 |
0.778±0.041 |
6 |
Annual survival (age 3–6) |
0.970±0.030 |
0.912±0.052 |
6 |
Annual adult survival (age 7+) |
0.890±0.053 |
0.967±0.028 |
6 |
Age at first breeding (yrs) |
4.40±0.130 |
3.88±0.130 |
5 |
Proportion of breeders |
|
|
|
1 yr old |
0.00 |
0.00 |
5 |
2 yrs old |
0.04 |
0.02 |
|
3 yrs old |
0.25 |
0.32 |
|
4 yrs old |
0.49 |
0.83 |
|
5 yrs old |
0.73 |
0.94 |
|
6 yrs old + |
1.00 |
1.00 |
|
Productivity |
0.390±0.055 |
0.562±0.041 |
1,4 |
Hunting mortality |
2159† |
0 |
this study |
|
|
1Bowser et al. 2009, 2Chapdelaine et al. 2001,
3Grecian 2005, 4Lavers and Jones 2007, 5Lavers
et al. 2008 a, 6Lavers et al. 2008 b. † Approximate
number of razorbills shot from the Gannet Islands based on the number of murres harvested in 2001–2003.
|