A reader writes:
I worked for many years with seabirds in California and Hawaii, and I wanted to add something about the differing impact of mortality between oil and wind. Oil affects predominately seabirds, whereas wind turbines affect mostly land birds. Land birds and seabirds have much different reproductive lives; seabirds live much much longer and produce fewer young each year. By way of comparison, the European Blackbird lays two clutches of eggs a year with around four eggs per clutch; a similarly sized storm-petrel (a tiny relative of the albatross) lays a single egg a year. The life expectancy of the Blackbirds is only 2.4 years, whereas the storm-petrels regularly live for decades.
The relevance of this to oil and wind? Adult mortality in seabirds is generally much lower than for land birds, under normal conditions. But increases in adult mortality are much less sustainable.
In a situation where you have a significant die-back of adults, land birds can sustain that die-back longer and rebound back much faster once that problem has been eliminated. The recovery time of seabirds is measured, however, in decades. For example, in California's Farallon Islands, the Common Murre was decimated from half a million pairs in the 1860s to around 3000 pairs due to egg collecting for food. Almost 150 years later that has recovered only to around 70,0000 pairs. So there is good reason that seabirds are the amongst the most endangered in the world.
It might interest your readers to know that millions of birds are killed every year when they collide with ordinary office buildings. Compared to this, the fatalities caused by windmills are small.
Daily Dead Birds is keeping track of the toll.
As if birds didn't have enough threats, they also have to look out for Randy Johnson's fastball.