The causes of death for radio-tagged quail on each study site and annual percentages for each predator type are represented in Tables 1 and 2. As shown by these tables, avian predators are responsible for a high percentage of over-winter mortality, while other predator types make up the lower percentages.
Table 1: Site 1 Causes of Adult Mortality
| Predator Types |
Nov. 02 - Mar. 03 |
Apr. 03 - Sept. 03 |
Annual
02 - 03 |
Nov. 03 - Mar. 04 |
Apr. 04 - Sept. 04 |
Annual
03 - 04 |
Nov. 02 - Sept. 04 |
| Avian |
9 |
30 |
39 (61%) |
7 |
26 |
33 (68%) |
72 (64%) |
| Mammal |
0 |
12 |
12 (19%) |
1 |
5 |
6 (12%) |
18 (16%) |
| Hunt |
4 |
0 |
4 (6%) |
2 |
0 |
2 (4%) |
6 (5%) |
| Unknown |
2 |
7 |
9 (14%) |
3 |
4 |
7 (14%) |
16 (14%) |
| Snake |
0 |
0 |
0 |
0 |
1 |
1 (2%) |
1 (1%) |
| Total |
15 |
49 |
64 |
13 |
36 |
49 |
113 |
Table 2: Site 2 Causes of Adult Mortality
| Predator Types |
Nov. 02 - Mar. 03 |
Apr. 03 - Sept. 03 |
Annual
02 - 03 |
Nov. 03 - Mar. 04 |
Apr. 04 - Sept. 04 |
Annual
03 - 04 |
Nov. 02 - Sept. 04 |
| Avian |
9 |
25 |
34 (59%) |
7 |
21 |
28 (57%) |
62 (58%) |
| Mammal |
2 |
6 |
8 (14%) |
1 |
12 |
13 (27%) |
21 (20%) |
| Hunt |
6 |
0 |
6 (10%) |
4 |
0 |
4 (8%) |
10 (9%) |
| Unknown |
4 |
4 |
8 (14%) |
1 |
2 |
3 (6%) |
11 (10%) |
| Snake |
0 |
2 |
2 (3%) |
0 |
1 |
1 (2%) |
3 (3%) |
| Total |
21 |
37 |
58 |
13 |
36 |
49 |
107 |
For both study sites, predation significantly increases by all predator types, except human, during the nesting season. Again, this is after spring burning when birds are more exposed. Also, the coveys are broken up and don’t have safety in numbers and are more vulnerable to mammalian predation while nesting.
Besides data collected from radio-tagged quail, the predation issue continues to be examined by a scent station survey. This survey gives an index to the mammalian predator population on the study sites. The survey is conducted each June and October. A scented disk is placed in a 3 foot diameter circle of tracking sand every ½ mile along roads and checked like a trap line. Twenty stations were placed on each study site and checked for 5 consecutive nights. The index is the average number of “hits” per night by known nest predators (raccoons, opossums, armadillos, bobcats) calculated as a percentage. Table 3 represents the predator indexes over the past 2 years on the study sites.
Table 3: Study Site Predator Indexes
| |
June 2003
% Hit
|
October 2003
% Hit
|
June 2004
% Hit
|
October 2004
% Hit |
| SITE 1 |
13% |
20% |
8% |
6% |
| SITE 2 |
13% |
19% |
17% |
17% |
An intensive predator control program was implemented on Site 1 following the October 2003 survey. As evidenced by Table 3, the mammalian predator index continues to decrease on Site1. The annual percent of mammalian predation on Site 1 has also decreased after initiation of the predator control program, as seen in Table 1.
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