05-10-2006 Council Agenda - Laserfiche WebLink

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THE CANADA GOOSE PROGRAM Dedicated to Urban Canada Goose Research and Management 2005 PROGRAM REPORT The 2005 Canada goose nesting and broodrearing conditions were nearly identical to those of 2003 and 2004. The spring was early and dry, and the heavy rains in May and June came after most nests had hatched thus few nests flooded. The rains produced an abundance of grass providing excellent broodrearing conditions until the dry spell during July limited forage and slowed feather development. As a result, most geese first flew in the last week of July rather then the more typical third week. Trapping and removal- -Geese were trapped at 132 sites and 4,357 (2,820 young and 1,537 adults) were removed in 2005, compared to 117 sites and 4,654 geese (3,156 young and 1,498 adults) in 2004 (Table 1). The number of trap sites was the highest ever. During the second week of trapping, the 85,000th Twin Cities goose was captured; a total of 88,211 geese have been removed from the Metro Area since 1982 (Figure 1). Productivity - -The average number of young geese hatched per nesting (brood patch) female was 4.2. A clear trend of decreasing production since 1999 is apparent when the data are graphed (Figure 2). Three factors are known to affect the number of gosling hatched per nest: late springs, high partial nest predation, and the age of the breeding females. The past three springs have been early rather than late and partial loss of clutches to predators was low in 2005 as well as prior years. The most reasonable explanation for the drop is the reduction of the breeding age of the nesting females. Prior studies have shown that younger (2 -4 years) females lay and hatch fewer eggs than older adults. Moreover, older females seldom abandon their goslings to other pairs (a phenomenon called "gang brooding "). Thus, as we trap repeatedly to reduce populations, the older females would be trapped first, leaving mostly young birds to nest. Trapping success and injuries - -The 2005 crews caught 94.5% of all geese and 97.3% of the flightless Metro geese they attempted to trap, just a bit higher than in 2004 (Figure 3). In spite of the near record heat in June and July, there were no trapping or transport mortalities, something -13-