A less rare crane's egg.

Fred HosleyA less-rare crane’s egg.

In Britain, common cranes used to be — as their name would suggest — all over the place. But as a species, they fell early to human thoughtlessness. Between hunters and habitat loss, they’ve been gone from the wild, in Britain at least, since 1600.

Conservationists have been trying to bring the birds back, raising them in captivity for the past three years. Now, one pair has laid an egg! And the conservationists responsible for the birds aren’t taking any chances: They’re putting that egg under 24-hour surveillance..

Besides the run-of-the-mill natural threats to the eggs, conservationists are worried about “an obsessive minority” of egg collectors who seek out rare eggs to add to their trove. Apparently some people are really, really into this pursuit. Back in the 1800s, for instance, one natural historian found a zone-tailed hawk’s egg, put it in his mouth to protect it from an Apache raid, and then let someone break his teeth to get it back:

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He was gagging from smoke and the still intact egg lodged in his mouth, and he couldn’t spit out the egg without breaking it. Try as he might, his swollen jaws could not open wide enough. Mumbling expletives at his first sergeant, Bendire ordered his men to have his mouth pried open to extract the egg.

Although they broke one of Bendire’s teeth in the process, he considered it a bargain for a perfect, uncracked zone-tailed hawk egg

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More recently, a “notorious egg collector” died in pursuit of an egg:

While a friend watched in horror, Watson, 63, lost his grip on the slender trunk of a 12-metre (40ft) larch tree he had climbed to check out yet another unusual bird’s nest. The former power station worker tumbled to the ground in woods in south Yorkshire, a region where collectors have often played hide-and-seek with police. Paramedics arrived soon afterwards but the father-of-three had suffered massive injuries and was declared dead at the scene.

The crane egg is just sitting there on the ground — no Apaches or trees involved. So maybe it’s not so crazy to think that someone might be thinking about wandering over and snatching it away. If they try anything, though, at least they’ll be caught on tape — a prospect that’s not likely to deter someone who’d be willing to give up his teeth for an egg.