Populations of blue-winged warblers, a type of bird, migrate south in the winter and return to Canadian breeding grounds in the
spring. As global temperatures have increased due to climate change, spring has started arriving in the warbler's breeding grounds earlier in the year, before the warblers return. Warblers now arrive at their breeding grounds too late to select ideal nesting sites and to feed on important early-spring food sources.
One way to remember this is when you are building a bridge there is one piece right in the middle that keeps the whole thing from collapsing that is called the key-stone. If a keystone species goes extinct then the rest of the ecosystem will crumble around it.
