Costa Rica and Panama have agreed to serve as “bridge” countries holding the migrants. At least three flights have arrived in Panama so far, and one flight landed in Costa Rica on Thursday.

In the interconnected web of nature, small disruptions can yield outsized consequences. One such example comes from Central America, where the decline of frogs and other amphibians is linked to a surprising and troubling outcome: a rise in malaria cases.

While Costa Rica joins Panama in holding deportees from mostly Asian origin until their repatriation can be arranged or they can seek protection somewhere, Honduras on Thursday also facilitated a ...