The population of least terns in Harrison County has dropped to several hundred mating pairs and their protectors are concerned about increasing destruction of the birds’ nests.

“The numbers are in a steady decline,” said Jan Dubuisson, chairman of the Least Tern Committee of the Mississippi Coast Audubon Society. “Terns were at their highs in the 1980s with 6,000 pairs. Now we have between 700 and 800 pairs. We don’t know why, but it could be a number of factors, nest predation, less ‘shiner’ fish to eat, environment.”

Audubon members have seen eggs destroyed in a number of ways. They hire guards to protect the nests during high traffic times, but that won’t stop an unleashed dog, bat-wielding boys or the feet of careless humans from squashing them.

Even deer grazing on sea grass have helped lead to the decline.

“Imagine how shocked we were when we saw the deer tracks,” Dubuisson said. “The deer wouldn’t deliberately kill terns, but they apparently come to eat the sea grasses near the colonies.”

Dubuisson’s group was formed in the 1980s to help the least tern survive.

It is the smallest North American tern, averaging about 8 inches. Adult males and females are alike in their white and gray coloring with short legs and a forked tail.

They breed mostly on sandy Southern shores and rivers and migrate to Central America for winter. Several subspecies are officially endangered.

The least terns are protected by the federal Migratory Bird Act, but that doesn’t stop unintentional destruction. The birds’ nests — divots in the sand covered by pieces of shell — can be hard to see.

They’re also susceptible to storms and tidal events.

When humans come too near a nest the parent birds will try to drive them off and drop excrement on the trespasser.

Dubuisson’s group flags each nest and hopes the public will respect them.

The birds begin nesting in April and most will continue their westward migration by August.

Dubuisson said the parents sit on eggs to cool them and do so by wetting their breasts, but not every mother tern is sitting on an egg.

“There are some funny stories,” she said. “We’ve found pairs incubating pecans and, once, a Timex watch.”