Bluebird nestling mortality in 2009
My observation is that there is less bluebird activity this year. I suspect it is because last summers cold & rainy weather increased the nestling mortality rate. My question: does anyone have statistics on the year to year nestling mortality rates of our PA Bluebirds? Michael of Bucks County.
Moderator of this Blog Said,
August 7, 2010 @ 10:08 pm
The Bluebird population is growing year to year because of conservation efforts through the many Landlords and monitoring of these nest boxes. Most of my studies indicate that 70% of Bluebird fledglings do not make it through the first year. On average, 40% die in the first 30 days after leaving the nest. This is when the fledglings are most vulnerable. After 90 days the juvenile’s chances increase. But another 30% do not make it through the first year. If I recall correctly, if they survive the first year the mortality rate drops to 20%. Now much depends on weather, availability of food, experience/age of the parents, geographic region, urban vs. rural areas, disease, pesticides and predators, etc. So the percentile varies.
In general, the more physically developed the young are when they leave the nest, the greater their chances are of survival. The quality of parental care, the number of siblings competing for that care, and the timing of fledging are also important factors.
Bluebirds dealing with nature, life become a challenge and so often the obstacles are so over whelming, but the bluebirds have met them head on; their perseverance is an example of that in the last 200 years. Of all the obstacles they must face, nesting sites should not be one of them. We can help increase the bluebird success rate by taking the first step, becoming a Landlord to these wonderful birds. If you would like to read more facts concerning Bluebirds please visit my website at ambassadorforthebluebirds.com http://livingroomtunes.com/newambassador/
Harry