Sunday, March 3, 2013

Beavers at May Pond and Their Unwelcome Scavenging Visitors

Beavers emerge from a hole in the ice at May Pond
Our Beaver colony continues to reside at May Pond, more than a month after the dam collapse at Secret Pond forced them to abandon their main lodge and winter food supply. But despite their hardships, all 7 beavers look well and appear to be healthy.
 A one year-old kit peels bark off of a poplar branch
Since the disaster, I've been providing them with emergency rations, and that seems to be enough for them to keep body and soul together. It has been a bit of a mystery why they haven’t been trying to retrieve more food for themselves – either from the fields or from the exposed food caches at Secret Pond, but the answer to that may have to do with the increased amount of predator activity around the nature preserve this winter – as I've written about in several recent blog posts.
Julia sits in the shallows and enjoys some willow twigs
This unsettling reality was quite literally brought home to the beavers this week when a raccoon died on top of the dam at May Pond, and a procession of carnivores turned up to claim their share of the carcass. I discovered the unfortunate deceased animal after I followed the tracks of a Fisher in the vicinity of Secret Pond. The tracks lead me to a nearly inaccessible portion of the May Pond dam.
Next to the dam, Julia and Blueberry pull strips of bark off of a log
On top of the dam, the footprints of no less than a half dozen predators and scavengers converged on the frozen and almost unrecognizable carcass of the raccoon. I initially thought that I could move the raccoon to a place where its popularity wouldn't be the cause of such consternation for the beavers, but I soon found that it was frozen tight to the dam - and it wasn't going anywhere. I thought it unlikely that I’d be able to dislodge it without taking a chunk of the dam along with it.
 Muskrats are far more vulnerable to the predators than Beavers
I decided to set up my trail camera up on the dam so I could see who exactly was putting the beaver’s nerves on edge. Even under normal conditions, a beaver dam serves as kind of a wildlife highway, but the added allure of a dead animal, turned it into a major thoroughfare. It's important to note, that though the presence of these predators may be upsetting to the beavers, none of them normally present any real threat to an adult beaver. An adult beaver easily out-weighs any of the carnivores that share their habitat at the nature preserve.
A one year-old kit climbs onto the ice to bust it down and enlarge the ice hole
The Crows were the first to be captured on video. A flock of 20 or more took turns tugging away at bits of the frozen carcass. A few arguments took place between them, but for the most part, the crows were good about taking turns and sharing.
Crows gather around the dead raccoon during the day time
An adult Red-tailed Hawk keeps its wings and tail spread out over its discovered feast

The next visitor – also by day, was an adult Red-tailed Hawk. This hawk probably had to fend off crows in order to get his turn, because the camera captures him striking a very aggressive posture. He hunches over his prize with wings and tail feathers spread – looking as large and formidable as possible, while at the same time covering from view as much of the carcass as he could. The camera’s microphone captured him voicing shrill warnings to all potential interlopers.
A Gray Fox comes to take its share well after dark
The fox stays alert during the entire time it spends with the carcass 
At around midnight, a Gray Fox visited the carcass and spent some time prying away at frozen bits of it. The fox stayed alert during the entire time and frequently looked up from his task to scan the darkness for other scavengers. At one point, the fox hears something, which causes him to spring to attention and to bolt over the dam in the opposite direction.
The Fisher shows up on the scene in the early morning hours 
About an hour later, the Fisher showed up and spent at least 10 minutes working on the carcass. This remarkably muscular animal is quite adept at pulling and prying off chunks. Although he remained aware of what was happening around him, he didn't seem as nervous about being there as the fox did.
The fisher feeds apparently unperturbed by any hungry competitors possibly lurking in the dark
Sensing the potential danger, the beavers were inactive for 2 successive nights. I know this mostly because they weren't captured on video, nor were their footprints found on the dam. However, on the 3rd night at least one of them did come by the carcass. On the video, an adult beaver leisurely walks through twice; I’m not sure which beaver it was since the camera didn't trigger until the beaver’s tail was just disappearing over the dam and into the water.

A raccoon with a bob-tail walks over the dam several times, showing understandable caution
2 nights in a row, a raccoon with a very short tail came by the carcass and briefly sniffed around the vicinity of the dam. This raccoon seemed justifiably concerned about what was happening here. Perhaps this is a relative or the mate of the one that died?  

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