May 25, 2013
Written by Jack Sanders
Thursday, 29 September 2011 10:59
Photographer Kevin Doyle, whose pictures of eagles and ospreys have accompanied this column and appeared on Audubon Web sites, was one of the many people who observed one of the indirect effects of Tropical Storm Irene on birds.
“On Sunday after the rain stopped and the sun came out, I found a cardinal’s nest about six feet off the ground and upon further investigation found three chicks in the nest. I thought it was too late in the season for them to have chicks, but apparently I was wrong. From my observations they were either hatched on Saturday before the storm or Sunday. One still had its eyes closed; the other two had open eyes so maybe they were a little older ... but the parents were nowhere to be seen.“All three seemed healthy and calling for food. Finally the male brought a grasshopper to the nest — fed them and that was it. After two hours of waiting, I called it a day.
“On Monday I checked the nest and two of the chicks were dead but the third was active. With all the noise Monday morning we never saw the adults and in the afternoon the male arrived with a grasshopper, fed the chick and once again never came back.
“Tuesday I checked the nest and the two dead chicks were gone. My question: Who do you think disposed of the chicks — the parents maybe? — since there was no evidence of a fight (the nest was clean).
“Then when I came home ... the third chick was dead. Wednesday morning the nest was void of the third chick and since then we haven’t the adults at all.”
Cardinals can raise between two and four broods in a single season, though four broods would be more likely in the South and unlikely this far north. Two broods are common here and three possible. Thus, chicks in late August may not be surprising, especially as our climate warms.
An interesting thing here is that two chicks were removed when a third remained. That seems to rule out a predator — which would presumably eat all the chicks, dead or alive.
It is possible that after the first two died, the parents removed them from the nest. Dead chicks represent a health hazard — if nothing else, the scent of carrion could attract potential predators.
The third chick may have become a meal for some predator — the parents would have no reason to remove the last dead bird since it’s unlikely the nest would be reused.
What would the predator be? A number of birds, including Blue Jays and crows, would prey on a nest of live or dead birds. Equally likely is a squirrel. We think of squirrels as seedeaters, but in fact, they are omnivorous, and are among the many threats that nesting birds must face.
The loss of the chicks may seem sad, even cruel, but both storm and predators can also be viewed as among the ways nature keeps bird populations from becoming too large (others include accidents, disease, and parasites). Studies have shown that in various species of songbirds, nearly half the eggs that are laid in nests never reach becoming nestlings. And up to 90% never reach breeding age.
Donna Warren of Ridgefield wondered why she hasn’t seen any goldfinches since the storm.
Farmers know one of the effects of high wind and heavy rain: Loss of crops. That applies equally to wild crops. All that wind and especially moisture could have destroyed many local supplies of thistle and other seed that goldfinches favor at this time of year. And like many other local songbird species, they may have moved elsewhere to find better food supplies. Even though we may keep our thistle-feeders full, birds do not rely on feeders for most of their food, and prefer wild sources.
HawkWatch Weekend and Green Bazaar, live birds of prey shows, kids activities, food, eco-friendly businesses, more, Saturday and Sunday, Oct. 1 and 2, 11 to 5, Audubon Greenwich, 613 Riversville Road, Greenwich, 203-869-5272 x239 greenwich.audubon.org.
Guided Bird Walks, Saturdays, Oct. 8 and 15, from 7 to 9 a.m., free, Audubon Green, 613 Riversville Road, meet in the main parking area, 203-869-5272 x239 greenwich.audubon.org
Birding with Luke Tiller: Saturday, Oct. 8: Allen’s Meadows and Secret Hotspots in Wilton, 7:30 a.m.; Saturday, Oct. 29: Sparrow Big, 7:30 a.m.; $10 each; To register visit www.sunrisebirding.com/walks.htm
Copyright 2011 by Jack Sanders. Send sightings or comments to: jackfsanders [at sign] gmail.com, or to Bird Notes, Box 1019, Ridgefield, CT 06877. If you need help identifying a bird, try your local nature center. If you find an injured bird, call wildlife rehabilitator Darlene Wimbrow of Redding, 203-438-0618, Wildlife in Crisis of Weston, 203-544-9913, or Wild Wings of Greenwich, 203-637-9822. The columnist’s website is www. sandersbooks. com.
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