尽管目前棕颈鹭没有被列入濒危名单，但由于寿命较长，繁殖率较低，它们的种群数量亦面临着严重的威胁。
Although the birds aren't listed as endangered, threats to their populations can pose serious risks, because the species has a long life span and a low reproductive rate.
值得注意的是，松鸡数量必需管理：如果荒野中松鸡过度繁殖，这种鸟类就会得病，导致种群数量暴跌。
Significantly, grouse need to be managed: if moors become over-populated the birds may become diseased and populations can crash.
当一个物种的种群数量稀少而又不得不近亲繁殖时，灭绝就会发生。
And this is what happens with small populations and inbreeding of close relatives.
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