Table 1. Number of black-headed gulls sampled per month for detection of avian influenza virus among 7,511 black-headed gulls, the Netherlands, 2006–2010*.
| No. sampled |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Y, Age | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
| 2006 | ||||||||||||
| FY | 0 | 0 | 0 | 0 | 6 | 365 | 0 | 0 | 0 | 11 | 74 | 70 |
| AFY | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 7 | 90 | 138 |
| 2007 | ||||||||||||
| FY | 96 | 28 | 1 | 0 | 0 | 167 | 37 | 0 | 1 | 6 | 100 | 73 |
| AFY | 72 | 39 | 0 | 1 | 34 | 2 | 0 | 1 | 1 | 4 | 153 | 275 |
| 2008 | ||||||||||||
| FY | 11 | 32 | 33 | 0 | 1 | 632 | 290 | 0 | 0 | 4 | 47 | 108 |
| AFY | 37 | 61 | 75 | 0 | 33 | 9 | 42 | 0 | 1 | 5 | 68 | 160 |
| 2009 | ||||||||||||
| FY | 169 | 43 | 0 | 0 | 0 | 295 | 383 | 0 | 0 | 0 | 45 | 57 |
| AFY | 740 | 172 | 3 | 0 | 31 | 82 | 55 | 0 | 0 | 0 | 56 | 288 |
| 2010 | ||||||||||||
| FY | 60 | 52 | 2 | 0 | 0 | 212 | 451 | 3 | 0 | 2 | 33 | 39 |
| AFY |
232 |
135 |
11 |
0 |
45 |
128 |
61 |
7 |
1 |
4 |
40 |
71 |
| *FY, gulls in their first year of life, comprising nestling and fledgling stages; AFY, after first year. | ||||||||||||