Odds are really good, especially as a Press Herald reader, that you’ve already heard about the otters at Evergreen Cemetery. This pair has been entertaining crowds and pleasing photographers for several weeks at this amazing green space maintained by the City of Portland. Before diving in with the otters, I do want to take a moment to commend the city and celebrate this space and all the wildlife it supports.

Ever since the otters showed up, we’ve been getting a lot of questions from people wondering where they came from, and, as it has gotten colder, what they’ll do as the ice sets in. First, I think it is worth acknowledging exactly what they are: officially known as Northern River otters, they are Maine’s largest mustelid (or weasel), and are not to be confused with sea otters, which are only found in the north Pacific. They are very aquatic, and built for it with their webbed toes and water-repellent fur. Otters have an amazingly diverse diet, eating everything from fish and frogs to insects, mollusks and, even occasionally, birds.

Many have wondered what effect, good or bad, the otters are having on the wildlife at Evergreen, and the best answer I can think of is: “They are the wildlife at Evergreen!” They are a native predator, and while you might feel bad for the fish that are getting gobbled up so quickly in the pond, don’t! A lot of those fish are actually goldfish that should have never been released in those ponds anyway. Even for the native prey, like the abundant frogs, there ought to be enough of them to survive increased predation, even from a novel threat. And even if the otters did manage to wipe out the frogs this fall, it’ll make those ponds an ideal spot for frogs to move to from vernal ponds next spring, as there will be abundant resources for them to take advantage. This is a bit oversimplified, but it’s important to acknowledge this is a natural predator-prey relationship at work: the ponds supported a ton of frogs until it was enough to support a pair of otters, then the otters will need to move on and the frogs will rebound.

Speaking of the otters moving on, by the time you are reading this, I’ll guess the ponds have become fairly covered in ice. The otters only need small openings as they can swim long distances under the ice, and the cold is not really a concern for them. But even if (or when) the ponds do ice over completely, there are plenty of places for them to move to, and it’ll likely be where they came from. I’ll bet they followed Capisic Brook up to the cemetery (we’ve gotten reports of otters at Capisic Pond many times before their sightings at Evergreen). And as you follow that water downhill, you get to Fore River Sanctuary and Stroudwater, which, thanks to its tidal influence, will have open water throughout the winter. (Side note: When I lived in Portland’s West End, I even found them at the former Mercy Pond. Makes me wonder if the conversion of that pond into more parking lots has contributed to the otters moving into preserved areas like Evergreen Cemetery.)

I am happy to see how the saga of the Evergreen otters has gone so far. I was initially worried about the amount of attention they were getting, as mammals can be especially sensitive to human disturbance, and crowds could have had a negative impact on them. So far, we’ve heard nothing but good behavior and complete respect and admiration from visitors. I’m thrilled that so many people were able to see and appreciate these otters, and hopefully see the value in these green spaces and the great work that the City of Portland has done to keep these areas wildlife friendly.

QUOTH THE RAVEN

Here is a fun question and perhaps one that has perplexed you or given you enjoyment in the field. Paulette Castonguay Poole wrote in asking about the common raven, one of my favorite birds to listen to, and its ability to mimic sounds.

Common ravens are the larger cousins of our more abundant American crows. It can be hard to tell them apart, but the raven’s larger bill, shaggier neck feathers, and wedge-shaped tail feathers can be helpful. As a fun fact, the scientific name for American crows is Corvus brachyrhynchos, which means “short-billed raven.” Another great way to tell them apart is by their vocalizations: the crow has a classic Mainer’s accent, saying “cah cah,” while ravens have a much deeper voice, often sounding like a lower “crock crock.”

Both crows and ravens, like many in the corvid family, have extensive repertoires of vocalizations. These can range from bell-like calls and hiccuping noises to some I can only describe as weird. One time I went bushwhacking in Orono because I thought I heard a baby crying in the woods. The closer I got, the higher up the noise was coming from, until I reached a tree where, sure enough, I discovered it was a raven.

There are a few in that family, like blue jays, that are well known mimics. They will often give imitations of hawks, especially broad-winged and red-shouldered hawks, which they do to scare other birds away from feeders so they can more easily get a quick meal.

Despite this trait running in the family, the research I could find showed that ravens don’t actually mimic noises in the wild. Their huge repertoire can produce noises that sound familiar to us, but none that are distinctly examples of mimicry. There are examples, however, of captive-raised ravens that could mimic noises they were taught, including, you guessed it, saying “nevermore.” For more on this topic, I highly recommend books by local naturalist Bernd Heinrich, especially “Mind of the Raven” and “Ravens in Winter,” which cover some of the amazing research Heinrich has done on these fascinating birds.

Do you have a nature question for Doug? Email questions to ask@maineaudubon.org and visit maineaudubon.org to learn more about backyard birding, native plants, and programs and events focusing on Maine wildlife and habitat. Doug leads free bird walks on Thursday mornings, 7 to 9 a.m., at the Gilsland Farm Audubon Sanctuary in Falmouth and, starting in January, monthly beginner bird walks in the Greater Portland area.

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