West Nile Virus hasn't been a big deal for most people, but it has been a problem for birds. For Crows, it has been a plague that has decimated populations in some areas.
Hi! I'm Iain MacLeod from New Hampshire Audubon, bringing you Something Wild.
West Nile Virus hasn't been a big deal for most people, but it has been a problem for birds. Crows have been particularly hard hit. In fact, for them, West Nile Virus has been a plague that has decimated populations in some areas.
This has provided biologists with an unusual opportunity, because crows are rather unique: they are extremely social and live in extended family groups. Young from previous years help their parents raise their siblings.
There aren't many birds that live this way, and in the Northeast, crows are the only ones that do. Because this is unusual, scientists can't help but ask questions. Why do they do this? What kind of competitive advantage does this give them? And where there are questions, there are theories. One popular theory was that crows were so common, there simply weren't enough breeding territories for all of them. If young crows couldn't find a place to raise young on their own, they helped raise their siblings, thus insuring that closely related genes were passed down.
Enter West Nile Virus. In 2002 and 2003, conditions were perfect for mosquitoes in Ithaca, New York, and in each year, 30 percent of the local crow population died. As a result, many breeding territories became available, so biologists waited for young adult crows to break away from their family groups to start their own families. But it never happened. Instead, survivors joined other family groups - sometimes even an unrelated family. Or remnant groups combined to form new families. It appears that crows hang around together by choice, not by circumstance.
Scientists are baffled. Are these birds making a mistake by choosing to stay in families even when the opportunity to go out on their own is there? Or is there some great benefit to their system that we just don't understand yet?
We are very lucky that the New Hampshire crow population has not yet been hit hard by West Nile Virus, although researchers think that it is inevitable. In the meantime, enjoy these complicated and mysterious birds in a new light. They are the best example of "family values" that I know.
If you have a natural history question that you would like answered on Something Wild, email us at somethingwild@ nhpr.org.
Something Wild is a joint production of New Hampshire Audubon, New Hampshire Public Radio, and the Society for the Protection of New Hampshire Forests. For Something Wild, I'm Iain MacLeod.
December 11, 2004: Indoor Spiders
Hi, this is Iain MacLeod from New Hampshire Audubon, bringing you Something Wild.
Winter has arrived and it seems as though everything is hibernating. Inside, however, it's a different story. It's actually a perfect time to observe our native household spiders as they continue to go about their business of hunting for food.
There are often three types of spiders at work in many homes: web-builders, active hunters and passive hunters.
Web-builders weave intricate nets to capture their prey. The small Cellar Spider has a gray or tan body and very long legs. It builds messy webs where it quietly sits, unless it's disturbed by something too big to eat. Then it shakes the web violently until the spider and the web are a blur, rendering both nearly invisible - a great means of protection.
Active hunters are often the spiders that startle you, since they actively chase down prey and they're fast! They may build a web to use as a resting retreat, but they do not use it to capture food.
A common example of an active hunter is the Jumping Spider. Small, dark and hairy with stocky bodies and short legs, jumping spiders can launch themselves many times their own length in a single bound. Because they move so quickly, they may seem frighteningly aggressive, but you only need to worry if you are their favorite prey - small insects.
The passive hunters sit quietly and wait for unsuspecting prey to pass by - then they pounce on it. Crab Spiders usually reside in your garden but you may find them indoors. They look like tiny crabs and can walk forward, backward or sideways. They also have excellent eyesight, which helps them to identify insects that are unlucky enough to get too close.
Use the quiet winter months to observe these small ferocious predators in action. They will eat many times their own weight in unwanted household pests - an excellent reason to keep them around!
Something Wild is a joint production of New Hampshire Audubon, New Hampshire Public Radio, and the Society for the Protection of New Hampshire Forests. For Something Wild, I'm Iain MacLeod.
If you have a natural history question that you would like answered on Something Wild, email us at somethingwild@nhpr.org.
