Tuesday, March 30, 2010

Beavers and robins

There's open water around the beaver lodge so I went over after sundown this evening to look for beavers. I saw 3. Two were floating near the lodge and both of these slapped their tails and went under when they saw me. The 3rd beaver was just below the dam and this one submerged silently and swam under the ice. I waited 5 minutes but it didn't come up. Beavers can hold their breath for 15 minutes or more and I'm sure this one just decided to wait me out, as it really didn't have anywhere to go other than back over the dam into the main pond.

While I was waiting for the beaver to reappear a robin started chirping by the observation tower. That is the first robin of the year for me. I got a blurry photo of my bird, a male, sitting on top of a spruce tree. There was another one calling further away toward Maxwell Lake.

Sunday, March 28, 2010

Pileated woodpecker nest testing

Pileated woodpeckers in this area often nest in a living aspen infected with a fungus called Phellinus tremulae. The fungus attacks living trees and rots the heartwood inside an outer shell of sound living sapwood. The fungus forms hoof-shaped fruiting bodies on the outside of the tree called conks. Hence the common name for this fungus - the horse-hoof conk. Although they are strong enough to chip away at very hard wood, even pileated woodpeckers don't like to excavate their nest cavities entirely in hard wood. Large aspens with heartrot are their favourite.

Each spring mated pairs explore for possible nest trees. They are well into the process for this spring, and yesterday I found a test excavation behind Maxwell Lake. There were actually 3 test holes on one tree. Perhaps the tree didn't have enough rot, because I couldn't see any fungal conks on the trunk and the chips on the ground were sound. There is dark hardwood at the back of the excavation however, which might mean rot is present. I'll keep watching the tree to see if the woodpeckers agree with me or not.

Sometimes a woodpecker pair will return years later to an old abandoned start and complete it for use as a nest cavity. There's some evidence to suggest that the original test hole might have actually introduced the fungus to the tree, in which case the woodpeckers are helping their own cause. Clearly the original tree met their requirements, but it didn't have enough rot. No problem, just inoculate the tree and come back later. A neat process to ensure a long-term supply of suitable nest trees.

Spruce buds and squirrels

Every year about this time tiny spruce branch tips appear on the ground. What's going on? Red squirrels are clipping the tips to eat the buds, which are starting to swell as spring advances. Squirrels don't have much to eat right now. Their winter cone middens are getting low, and not much new growth has started. The spruce buds are probably both nutritious and tasty, at least until something better comes along.

I've watched squirrels clipping the tips. They're pretty quick, clipping the twig, turning it to bite off the bud, and dropping it almost in one motion. The first time I watched this activity I had a hard time picking up the bud removal part even with binoculars. To complicate things, sometimes the squirrel clips the twig and just drops it. I don't know if that's deliberate, but I suspect it is. Maybe the squirrels can discern whether or not the bud is a good one, or maybe the protective nest of needles on some buds is too much trouble.

I have another theory about the significance of this. Spruce cone crops are variable, with several years of low crops followed by a bumper crop. Red squirrels actually have bigger litters in the bumper year. This makes sense - the young squirrels will have better survival if there's lots of food for them in that difficult first winter. But what signal causes the squirrels to have bigger litters, which are born before the cones ripen in the late summer? Perhaps this twig clipping is a way to measure how many of those buds are normal vegetative buds, and how many are reproductive buds which will form male and female cones. Whatever the mechanism is, the squirrels somehow know when it's time to have lots of kids. Amazing.

Monday, March 22, 2010

Owls calling

This evening I hiked up the Happy Creek Trail and put up 2 more duck nest boxes on the upper beaver ponds. I'll do the last 2 tomorrow evening. Carrying a box in each hand all the way up there is hard work. It doesn't seem they weigh much but carrying them for a few km on slippery trails definitely got my arms complaining. The highlight was a barred owl that decided to hoot a few times from pretty close range while I was putting up the first box. I absolutely love barred owl calls. It only called twice. I waited awhile and then tried to imitate it but got no response.

After I hung the second box I detoured off the trail to check one of my old pileated woodpecker cavity trees and got rewarded when a boreal owl stuck it's head out of the hole right at dusk. It didn't stay at the entrance for more than 15 seconds and no amount of scratching on the tree could get it to look out again. There were downy feathers stuck to the entrance which could mean this little owl might have been using that woodpecker hole for some time. Two owls in one evening was pretty good fortune in my books. Some of the Whisky-jack club folks went out last Saturday night and got a northern saw-whet owl calling on the downstream boardwalk loop along Happy Creek. This is the time of year when one is most likely to find an owl or two calling from just before dark on into the night.

Sunday, March 14, 2010

Waterfowl Platform Raised

Last year I misjudged the high water mark on Maxwell Lake, and the waterfowl platform we put in at the east end of the lake became the submarine platform instead. Recently I added another 2x8 frame and filled it with soil. I also put a smaller box on top with wood chips and sedges in the hope that a Canada goose pair will nest there this spring. And finally I seeded grass and spread fertilizer to get some green going.

It was pretty windy, so the photo looks a little messy from all the windblown dirt. That will fall to the lake bottom when the ice melts and the platform will look even better when the grass sprouts.

While I was there a troupe of chickadees was calling over by the lake tower, and several birds were noisily calling the "fee-bee" song that's always an early sign of spring. Pussywillows are out too at the end of the lake. All we need is an extended period of warm days and winter's grip will be broken.

Tuesday, March 9, 2010

Waterfowl Nest Boxes

Last Sunday I put up 7 waterfowl nest boxes around Maxwell Lake and the lower Happy Creek beaver ponds. Two boxes are close to the observation towers, in the hope that if a duck uses them her comings and goings will be observable from the towers. The rest of the boxes were put in quieter spots, where a duck hen might feel more comfortable setting up housekeeping without those curious human eyes close at hand.

Which species might use the boxes? The common goldeneye and bufflehead are the 2 most likely to take up residence. Both species always use Maxwell Lake during the spring migration period and might decide to stay and raise a family. If we're fortunate, maybe Barrow's goldeneye or hooded merganser might show up, and at an outside chance (pretty low chance, I admit) maybe a wood duck. That's about it for cavity-nesting ducks, but we can also expect to see other species using the boxes. After all, a hole in a tree is a home to many. Small owls and squirrels will certainly take up at least temporary residence, and other species that like cavities like bats will likely use the boxes at times.

I meant to number the boxes but forgot until after I had the last one up. Next winter when I check them for signs of use and to give them a good cleaning I'll add the numbers. In the meantime, if you see any wildlife using the boxes, please let me know. I'll report here in the blog.

One last thing - it's been reported that some duck hens actually might select their nest site during fall migration the year before. So if we get no takers in 2010, there's always hope for next year!

Wednesday, March 3, 2010

Signs of Spring

To go with the recent warm weather we have the earliest of spring birds starting their annual cycle. Crows, Canada geese, and bald eagles have all been spotted in the last few days. Two days ago I saw a magpie carrying nest material into a young spruce tree where it was busy making it's nest of sticks.

Every spring I watch for the arrival of the thrush cousins, the American robin and the varied thrush. It seems to be a race between the two - some years the robin arrives first and others it's the thrush. Sometime in the second week of April is about right for Hinton. Who will be first in 2010?

This weekend I'm going to put up some duck nesting boxes around Maxwell Lake in the hope that a few cavity-nesting species such as the common goldeneye and bufflehead will make the area their home this spring. Watch for the boxes mounted on trees and let me know if you see any ducks entering or leaving.