Jeanette Gibson outdoors column: The murder of crows
A flock of crows is sinisterly referred to as a “murder” of crows. Two decades ago, it seemed as if someone or something was actually out to do just that - murder the crows.
Here at Gibson House, the presence of crows in the yard is something that has been much more of a rare treat than an everyday occurrence for the past 20 years.
Back in the early 2000s, finding dead crows in Illinois became a common event as the crows began to test positive for the West Nile virus. What was once a thriving and abundant crow population was absolutely decimated.
Before the West Nile virus, Illinois had boasting rights to the largest gathering of American crows in the all the world.
Each year, over 300,000 crows arrived to Danville from all over the Midwest to overwinter near Lake Vermillion.
Just a year after West Nile virus was detected in two Chicago crows, estimates are that half of all Illinois crows had already died from the virus.
2002 saw major deaths in the robins and blue jays as well.
Estimates are that 70% of crows that contracted West Nile virus died from it, typically within 24 hours.
2002 also saw many Illinois human residents get sick and die from the West Nile virus.
Scientists quickly learned that there was a link between the declining crow population and how the West Nile virus spreads. They also learned how to contain it.
West Nile virus is spread between birds, even birds of different species. Humans get West Nile virus by being bitten by a mosquito that has previously bitten an infected bird.
It wasn’t the crows, however, who were the “super spreader” of the West Nile virus among the bird world. It was the American robin.
It seems that mosquitoes feed on robins more so than any other species of bird, with Illinois hosting large numbers of returning robins during the spring every year.
With mosquitoes feeding on robins who carried the virus in their blood, the virus was more easily spread to other birds and even humans.
The American crow is now known as an “indicator species” in that when their population begins to fall, we know something is amiss.
The good news is that crow populations are again growing here in Illinois. These highly intelligent birds are adaptable to many environments and are not shy of human interaction - especially where food is concerned.
Crows do not typically visit bird feeders, but will on occasion if they are comfortable. They eat everything from worms and insects to small animals and fruit.
Crows are a big part of nature’s clean up crew - helping to clean up carrion.
This spring I have noted that the crows nesting in the big tree out back are more numerous than in years past. As the spring progresses, there will be more fledgling crows hopping about in the garden and learning that my Nature Center is a friendly place for occasional treats.
This article originally appeared on Star Courier: Jeanette Gibson outdoors column: The murder of crows
