A common loon sits on a nest along the shore of Lake Auburn. Loons need to nest along the shore, and boaters can ruin a nest by not regulating their wake near the shore. Daryl Slover/Sun Journal Buy this Photo

Summer in Maine for many means it is time to head to the countless lakes and ponds around the state for rest, relaxation, and making babies! At least that last one is what our iconic common loons are doing, though there is definitely no rest or relaxation for them.

Because there are so many people using the same lakes as loons, we often hear about conflicts between the two. I want to cover a few things we all can do to help our charismatic common loons have a successful nesting season while we enjoy their waterways.

One of the chief threats to common loons during nesting season is lead poisoning, usually stray lead fishing tackle ingested by the birds. Carl D. Walsh/Staff Photographer

First, it is important to know that loons are nesting on freshwater lakes and ponds because of the steady water level, which they need to be able to access the nests they build right on the edge of the water. A loon’s legs are so far back on its body that they are basically useless for walking on land, so they need to have  nests right at the shore. This is also why loons, who spend the winter on the tidal ocean, can’t nest there.

A big anthropogenic problem for loons on lakes is from boats and other watercraft. It only takes one big wave to flood a nest. Trauma from boat strikes causes over 40% of chick deaths. These can both be avoided or minimized if boaters obey the no-wake law within 200 feet of shore, and especially slow down when passing nesting areas.

Second, the No. 1 cause of mortality in adult loons – 53% of cases during the nesting season – is lead poisoning. The lead that loons are ingesting comes primarily from two sources: jigs and sinkers. Often loons get lead in their system by eating a fish that has swallowed the tackle, but lead tackle that sinks to the bottom of a lake can also be easily picked up. Loons will often swallow small pebbles they pick up off the bottom of a lake to help grind up food in their gizzard, but unfortunately also ingest lead tackle this way. So before you go fishing, make sure you swap out any lead tackle you have. You can do this for free thanks to “Fish Lead Free” programs in the northeast that will exchange tackle with you, provide lead-free tackle boxes for kids, and more. Learn more at: fishleadfree.org

You can also help by being an advocate for loons, and joining Maine Audubon’s Annual Loon Count. Since 1983, this survey of loons across the southern half of Maine has helped provide a valuable insight into the nesting productivity of perhaps our most iconic nesting bird (though puffins also compete for that title, nothing beats the mournful wails of a loon reverberating across a lake). In 2020, the estimated population (for the southern half of Maine) was 2,974 adult common loons, and 414 chicks. The count is on July 17 this year, and there are still a few lakes that need coverage. Even if your local lake has volunteers already, we always need people to do more outreach and share with visitors the importance of mindful boating and fishing. Learn more about the Annual Loon Count, how to participate, and more, at: maineaudubon.org/looncount

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So many reasons why a nesting might fail

Other birds are reproducing, too, and many people have sent in photos or asked questions about bird nests and chicks. Laura McCann Tripp wrote in, saying she has had phoebes nesting for the past three years at her house. This year, she found all four babies dead on the deck, and wonders what she can do to help them stay safe if they return next year.

With our typically-limited views into the nesting nature of most birds, eastern phoebes often offer an up-close and personal glimpse into their dramatic nesting attempts. This is because phoebes look for nesting sites that provide a bit of cover from the elements, and while a natural rock outcropping works great, the rafters under a man-made porch work even better. Not many birds will literally nest on your house, but phoebes have become well known for this and that means we get to see the trials and tribulations of nesting unfold right in front of us.

Eastern phoebes are hard-working parents and will raise multiple broods, each averaging four eggs, in a single summer. They overwinter in the U.S., but mostly south of New England, so they are early to arrive here in the spring and don’t wait long to start nesting. After pairing up and building a nest, the first eggs are laid in about a week, and the incubation period averages around 16 days. Like many songbirds, their young are altricial, born with no feathers, eyes closed, and completely dependent on the parents for care.

They develop very quickly, which is fortunate because being stuck in the nest is a very dangerous place. You could almost say they are “sitting ducks.” Within 15 days of hatching, with nearly nonstop feedings from the adults, the phoebe chicks are capable of flight and will leave the nest. This is the start of the very awkward couple of days in their lives where they are not good fliers, and are still being fed by the adults. As mentioned in a previous column, this is when humans need to just leave them alone. The desire to “help” is likely to cause more harm than good.

That assumes that everything goes correctly through the nesting process, but as Laura has observed, it doesn’t always go as planned. It is always hard to know exactly what caused a nest failure, but there are some common culprits. Adult phoebes are excellent parents, with the female spending a lot of time brooding the young, so exposure to the elements is rarely a problem. However, if something does happen to the female, like being caught by an outdoor cat (seriously, keep your cats indoors), then the male will continue to feed the young but doesn’t take on the brooding responsibilities. This can lead to death by exposure or starvation if the lone male isn’t bringing enough food.

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Again, being altricial and having few to no feathers means that it is really hard for chicks out of the nest to survive long. In pairs where the male disappears (again, odds are really high it is because of an outdoor cat), a replacement male may kill the chicks of the previous male, toss them out of the nest, and start a new brood of his own.

There’s something else worth mentioning, too: brood parasites. Eastern phoebes have a remarkably high rate of nest parasitism by brown-headed cowbirds, with some states reporting around 20% of phoebes’ nests having cowbirds dropping in an egg. The phoebes will unknowingly raise the cowbird chick, which grows much faster than the phoebes. It will be more dominant at feedings, and sometimes push the phoebe chicks out of the nest.

I often get questions from people with phoebes nesting around their houses, who have spotted a cowbird egg in the nest, and want to know if they should take it out. The simple answer is: No. It might seem bad to you but this is a natural process and we shouldn’t project our own values on the cowbirds. Plus, it is illegal! Taking eggs out of a nest is a violation of the Migratory Bird Treaty Act. If even that doesn’t stop you, consider this: a study in 2007 found that female cowbirds will keep track of the eggs she has laid in the nests of others, and if they are removed, she’ll retaliate and destroy that nest and the remaining eggs.

I hate to be a downer, talking about all the things that can go wrong at a nest, but I hope people’s experiences with phoebes help to give us a window into the many difficulties that these birds have to overcome. So turn off that episode of “Days of Our Lives.” There is enough drama happening right on your porch.

Do you have a nature question for Doug? Email questions to [email protected] and visit maineaudubon.org to learn more about bird walks, community science projects, and other programs about wildlife and habitat.

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