Yesterday I noticed several Sitka Alder with new leaves. Some of them were clearly still developing, and given the lateness of season, I thought this seemed odd. I am guessing the warm August/September (so far – though it seems to be cooling off now) had something to do with it.

I found myself wondering what the break even point for a leaf is. It seems like it would take a fair amount of energy to grow a leaf. Clearly over the course of a leaf’s life, it must generate more energy via photosynthesis than it too to grow (or at least it must on average for a tree). So I wonder what the break even point is. My guess is these new leaves aren’t going to bring in as much as they cost due to the lateness of season, but I don’t really know.

If anyone knows of research into the break even point of leaves, I would be curious to see it.

I got an e-mail this morning from someone who reported seeing a dozen or so geese off the point at Totem Park this morning. She said it was dim and she didn’t have binoculars so couldn’t see them too well, but it looked like they might not have white cheeks, and might be worth checking out. I took this as motivation to get out of the house – something I might not have done otherwise.

By the time I headed out, skies were getting darker and snow was starting to fall. When I reached the park snow was falling heavily. Between the wind, snow, and moderately low tide, I couldn’t see the water at the end of the park, and I didn’t really want to wander out into the stiff breeze with blowing snow. Instead, I spent a little more time on the trail, gave some attention to the two species of alder, then walked over to the river mouth, and finally to the point, by which time the snow was starting to let up.

I walked out on the flats and was able to approach some of the 100 or more crows fairly closely. They seemed to be foraging for invertebrates and eating snow. It was fun to watch (and try to photograph) them flying up with mussels (I think) and dropping them to crack them open. I got pictures of several different individuals, but not a good full sequence for any particular time. I sorted the gallery pictures below so it’s in order, even though the pictures are from 2 or 3 different birds. One particular crow allowed me to approach quite closely as it was eating snow. I was interested in this, since Rowan had just told me a couple of days ago that she was able to see the crows eating snow at the park.

After heading back to the trail, I stopped to take pictures of 5 different alder trees. I like to try and notice differences between the species of alder (Alnus rubra and Alnus viridis) – and I think I found another one today. It seemed to work pretty well for the trees I could find at the park today, anyway.

[Show slideshow]

Northwestern Crows pick up molluscs and fly up before dropping them and racing down to grab the cracked shell before another can steal it.

Northwestern Crows pick up molluscs and fly up before dropping them and racing down to grab the cracked shell before another can steal it.

Northwestern Crows pick up molluscs and fly up before dropping them and racing down to grab the cracked shell before another can steal it.

Northwestern Crows pick up molluscs and fly up before dropping them and racing down to grab the cracked shell before another can steal it.

The Pyramids are mostly obscured by falling snow in front of them.

Northwestern Crow eating snow from the beach.

Northwestern Crow eating snow from the beach.

Black Oystercatcher at Totem Park.

Can you identify the species of Alder from the bark?

Can you identify the species of Alder from the bark?

Can you identify the species of Alder from the bark?

Can you identify the species of Alder from the bark?

Can you identify the species of Alder from the bark?

While helping with environmental survey work at Blue Lake a couple of summers ago, this alder branch broke along where we had cut a trail through an avalanche path brush field adjacent to Blue Lake Creek. I am not sure what created the bore hole, but my guess is a beetle of some sort. It seems likely that the branch broke where it did because it was weakened by the hole. I may be that the hole provided an opportunity for decomposing fungi to get started, which would have further weakened that location. It’s probably not easy to get the identity of the borer based only on these excavations, so I suspect this will remain a mystery for quite some time.

I was a little surprised to find an active caterpillar on the branches of Sitka Alder (Alnus viridis) in February.

While down at Lincoln Street Beach the other day with Connor, I happened to notice this caterpillar crawling around on the branch of a shore-side Sitka Alder (Alnus viridis ssp sinuata). Later I found a couple of others, though I was unable to relocate the first one. They blend in to the branch quite well, so I was lucky to catch the first one moving. After knowing where to look and what to look for, I was able to find the others even when they were not moving.

I was aware that some species of moths and butterflies overwinter as caterpillars, but I have not previously found any here (not that I’ve been looking), nor did I expect there would be ones that are active in exposed locations through the winter. I’m making the assumption that these caterpillars have been active through the winter, as it hasn’t been so warm in recent days that I would expect things to decide winter is over. In any case, it seems likely that these caterpillars have a reasonable tolerance for freezing conditions. I found them on the ends of branches with no cover, so night-time temperatures on cold days would almost certainly get below freezing. I don’t think they could crawl back down the tree fast enough to take shelter in the dirt, but I could be wrong about that, I suppose.

There is some question in my mind about what these are eating. Given where I found them, it seems likely they are eating some combination of bark, buds, or developing catkins on the alders. It also seems possible, though unlikely, that they are just hanging out, but not eating, for the winter waiting for the leaves to emerge in the spring. If this is what they are doing, I see little advantage to being active at all over the winter, in fact, it seems like it would be a big disadvantage due to increased chance of death due to weather or predation. On a bud not too far from one of the caterpillars I found, I did notice a little bit of damage on a leaf bud. It could have been from a caterpillar chewing on it, but I’m not sure whether it was or not.

I was a little surprised to find an active caterpillar on the branches of Sitka Alder (Alnus viridis) in February.

I was a little surprised to find an active caterpillar on the branches of Sitka Alder (Alnus viridis) in February.