Band(ing) of Brothers: Hoodies and Woodies
During the 2010 nesting season, Peter monitored 94 nest boxes on Duck Creek. Wood ducks made 67 nest attempts and laid a total of 1,030 eggs. Out of these, 651 ducklings hatched and exited the nest box; 550 of these birds were fitted with specialized leg bands (oval stainless steel bands, lined with clay to allow the birds to grow into them). This year the proportion of laid eggs that produced ducklings (63 percent), as well as the overall nest success (73 percent), was higher than the long-term average.
The higher percentage of success for Wood Ducks can be explained by elimination of predation by raccoons, which was exceptionally high in 2009. New predator guards below the nest boxes, especially those using PVC pipes, worked very well at keeping the raccoons out this year. However, a total of 12 nests (18 percent) were abandoned; some part of this loss can be attributed to persistent unsuccessful attempts of raccoons to climb boxes. Although no predator guards can prevent black rat snakes from entering boxes, only four nests (6 percent) were depredated by these snakes. In addition, two nests (3 percent) were lost to birds pecking holes in the eggs, most likely northern flickers or red-headed woodpeckers.
Hooded mergansers made 24 nest attempts and laid a total of 334 eggs. Seventy-one percent of these eggs hatched, producing 242 ducklings that left the nest boxes; of these, 226 ducklings were banded. For Hooded Mergansers the nest success was similar to the 15-year average (74 percent). Only one (4 percent) merganser nest was depredated and five (21 percent) abandoned for unknown reasons.
On average the nest boxes produced 9.5 ducklings in 2010 (8.6 in 2009). Many boxes received more than one nest attempt and several boxes produced two successful broods. For example, a nest box located at Pool 2 (# E87) produced a total of 26 ducklings (12 mergansers and 14 wood ducks) during the 2010 breeding season. To enhance repeated box use old nesting material (including egg membranes and shells) was removed, boxes were cleaned and fresh bedding was added as soon as ducklings exited.
Overall, it was a good summer, with 893 ducklings (Hoodies and Woodies combined) leaving the monitored boxes, which was higher than the long-term average (844) at Duck Creek CA. Over the past 15 years the number of Hooded Mergansers using the nest boxes has increased. The number of little Hoodies produced in 2010 was highest recorded.