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Archived Postings

July 4, 2005 – July 10, 2005

July 4 to July 10, 2005 Breeding season is fast coming to an end. Many young have fledged from their nests, while the others are close. Now comes the difficult bird-watching season. The majority of bird-watching is by ear. In most cases, you’ll hear the birds well before seeing them. The breeding calls of the adults used to attract mates and define territories are not needed during the fall so the frequency of songs is reduced and replaced with call notes. Young birds have no reason to sing so they also give call notes. The morning chorus of bird songs is replaced by chips, cheeps, and chirps, leading to the frustration of figuring out who is who. Differentiating call notes comes with practice, but it is a nice treat when the birds do sing their song. The other difficult part of fall bird-watching is that the majority of songbirds go through a moult that results in their winter plumage. Adult birds from many species will replace all their body feathers and flight feathers before starting fall migration and lose their brightly coloured breeding plumage. The resulting plumage from this moult can make it difficult to identify males from females and often young from old birds. In some cases, especially with wood-warblers, birds will lose some identification features that are used to separate species. The other challenge comes from the young. Fledglings will also have a moult before they begin their fall migration. When they leave the nest they are in juvenile plumage that has very few identification marks. They will moult body feathers before migrating into a plumage that often resembles the female winter plumage. Some comfort will come in knowing that in species that are sexually monomorphic (the males and females have the same plumage) fall plumage is almost identical to their spring plumage. Depending on the species, moult strategies can be simple while others are complex. Most identification books have pictures comparing many of the possible plumages. Don’t get too discouraged…….

2010