peteythedancingsabre wrote:
From what I've read about this stuff, this kinda thing happens quite often, it's just that people happened to notice it this time. Granted, there could be something that caused this, but large numbers of animals die quite frequently, whether it be by disease, lack of food, or countless other things that can affect a population. Not necessarily something to cry foul about.
it's not very frequent.
and there are about four things that cause (fast onset) mass death - disease, anthropogenic infringement on ecosystems, natural life history, or environmental stochasticity (weather events, unbalanced sex in recruited youth).
salmon are an example of natural life history die off. they spawn then die. disease often is tracked and we can watch it happen and it's not a surprise (like tasmanian devil's facial tumor disease). weather events like spring turnover in lentic ecosystems (ponds and lakes) result in increased oxygen demand so you'll see things like turnover kill, which is when stratified water "flips" layers and certain fish die of anoxia. rarely you will see breeding populations suffer from too many males/too few females or vice versa and that can lead to smaller populations.
the blackbirds dying was due to fireworks being lit off. it scared the crap out of these birds and they flew into buildings and stuff and that's why they found physical trauma throughout all of them. some people were claiming the birds just dropped out of the sky dead.
most mass die offs are due to anthropogenic infrigement. it's not as natural as you may be lead to believe...because the natural dieoffs are documented by now. especially for animals that aren't insects or extremely rare.