Maybe you’re like us and you spend all your free time watching the 24-hour eagle webcam, and now you have a few questions. For instance, why do the eagles wear wing tags? And what happened to the two chicks that hatched on Santa Cruz Island in 2006?

Nature.org recently caught up with Lotus Vermeer, director of The Nature Conservancy’s Santa Cruz Island Preserve, to find out more about the nesting bald eagles featured in the 24-hour live webcam.

nature.org: First of all, we heard that one of the eggs in the nest recently broke. Why?

Lotus Vermeer: Originally there were two eggs in the nest, but one egg broke in late March. There are a number of natural factors that could have caused the egg to break. It’s possible that the egg was unfertilized and not viable and broke. Or the shell could have been punctured by a twig in the nest. It’s also a remote possibility that the fragility of the egg was related to DDT contaminants. But sometimes these things just happen — bald eagle eggs typically have a 50 percent survival rate.

We also had an egg in another nest on the south side of the island, but that nest has failed. There's a possibility that a third pair of eagles will nest, or have already and we just haven't found their nest. So right now all our hopes are on the one remaining egg, which is expected to hatch sometime around April 9-12.

nature.org: Which bird is male, and which female? Does she do all the nesting, or do they take turns?

Lotus Vermeer: "K-10" is the male and is 6 years old. His mate, "K-26," is the female and is 5 years old. They take turns incubating the egg in the nest.

nature.org: Why have the birds been tagged? How does NPS/IWS monitor the birds?

Lotus Vermeer: These birds are part of the Montrose Settlements Restoration Program/Bald Eagle Re-establishment, which is administered by the National Park Service. The birds are tagged with numbered patagial wing markers and banded with USFWS metal leg bands. Orange tags (as with K-10 and K-26) mean the eagles are from the Catalina Island re-establishment program, while eagles with blue tags are from the Santa Cruz Island program.

Bald eagles were introduced to Santa Cruz Island as 8-week old chicks, and were sourced from wild nests in Alaska and from the San Francisco Zoo. The chicks were reared for a month in hack towers — large nesting boxes about ten feet off the ground where the birds test their wings and adjust to the island's breezes — and then released from these towers when they were 11-12 weeks of age, which is the age that they would normally fledge, or fly from the nest.

Prior to release, the birds are marked with the blue wing tags, leg bands, and also fitted with a lightweight backpack-mounted telemetry transmitter. The telemetry transmitter allows for the birds to be tracked for several years as they move either among the islands and/or off the islands to the mainland.

nature.org: Is this nest the same one the pair used last year?

Lotus Vermeer: Yes, it is the same nest. Bald eagles usually fix-up and use the same nest year after year, so they don't have to reconstruct a new nest entirely from scratch. Building a nest is a huge investment of energy.

nature.org: How did the NPS/IWS get that camera up there without disturbing the birds?

Lotus Vermeer: With great care and difficulty! All of the equipment and materials — camera, webcam, satellite dish, batteries, etc. — had to be carried by hand up the steep canyon on the other side, and out of view, from the nest.

nature.org: What's on the branch above the eagles? They keep on gnawing on it.

Lotus Vermeer: Some viewers speculate that every now and then the parents get a bit annoyed at that branch, especially when they stretch their wings and get tangled in it. They gnaw on it, possibly to try to cut it off, or perhaps to vent frustration. We don't really know for sure.

nature.org: The eagles seem to be pushing or turning the eggs. Why are they doing that?

Lotus Vermeer: Many birds do this to distribute heat more evenly on the eggs. This also helps to keep the inner egg membrane from sticking to the inside of the shell. On the webcam, the parents can be seen wiggling down into the nest when they switch over from one to the other for incubating duties. This is so they can expose their brood patch (a featherless area on their abdomen where they can more easily transfer heat from their body to the egg).

nature.org: What happened to the chicks that were hatched last year — are they OK?

Lotus Vermeer: Not just one, but two bald eagle pairs nested successfully and produced chicks on Santa Cruz Island last year — the first bald eagle chicks to be born in the wild on the Channel Islands in half a century! K-10 and K-26 produced a female chick, A-49. She is doing well, and has been spending much of her time on Santa Cruz Island, as well as on Anacapa and Santa Rosa. The second chick, A-60, a male, is also doing well, and has been regularly spotted along with A-49.

nature.org: What does this pair nesting again on Santa Cruz Island say about the ongoing restoration of the island?

Lotus Vermeer: Our efforts to restore and protect the island have been a great success. We have tipped the balance back in favor of the island's natural systems. Through our actions, destructive non-native animals (e.g. sheep, pigs) have been removed, the endangered Santa Cruz Island fox is recovering from the brink of extinction, and unique native plants are making a dramatic recovery. The island can now begin to recover on its own provided that we continue to facilitate the healing process through stewardship, sound science practices and vigilance. The re-nesting of this pair brings great hope that bald eagles will once again populate the Channel Islands.

Nature picture credits (top to bottom, left to right): Photo © Mary Claypool (Bald Eagles); Photo © Walt Denson (Lotus Vermeer)