My primary impression of winters in Sitka is not so much shaped by cold temperatures or the amount of snow that falls, but rather what happens in the days after it snows. When a high pressure from the Yukon pushes over Southeast Alaska, we can get a period of days to even a couple weeks of temperatures down into the 20s and teens. As the high pressure weakens together with a low moving in from the Gulf of Alaska, it’s not unusual to get a day or two where snow falls before it warms enough to become rain. All too often, it seems like the temperatures rise to only just above freezing and remain there for several days. It’s also not unusual for there to be wind and decent amounts of rainfall as well. Today was a day like that.

Late last night I noticed the snow in the backyard seemed exceptionally bright, so I stepped out on to the front porch to have a look. High in the sky towards the south, I could see the practically full moon shining through a thin layer of clouds. This break in the heavy cloud cover allowed the ground to cool off dramatically – something it did not need that much help with considering all the snow, slush, and ice that was already there. By the time the sun was rising, heavy clouds were back, and it had started to rain. Over 3/4 of an inch fell throughout the day, and with snow and ice effectively blocking drainage down and over the surface, pools of standing water formed. Where foot or vehicle traffic had been adequate to compact the snow, but not enough to wear it completely away, this resulted in a layer of water over a sheet of ice. These treacherous conditions are one of the hallmarks of a Sitka winter, for me.

My memories of winter are probably shaped in no small part by the 4+ years I spent walking my paper route five days a week delivering the Sitka Sentinel. The physical difficulty and discomfort of walking along the icy and slushy sidewalks and side roads (or getting sprayed by slush churned up by passing motorists on the main roads) in cold rainy and dark conditions probably makes these times stand out more to me than they might for others. I don’t really remember how I felt about it at the time, but these days I do not mind it too much. It can be a little annoying when I catch an especially slippery spot of ice and land on my butt in a puddle of ice water, but fortunately that does not happen too often. It can even be fun to sort of skate along the lumpy sidewalk ice like I did a bit this afternoon.

I only got outside briefly today. I decided to take a short walk over to the new house to see what progress they had made since yesterday. Around the house through the course of the day I noticed the usual suspects calling – even heard some Varied Thrushes through the windows this morning. Connor and Rowan were excited by Pine Siskins visiting the feeders they had set up. They tried, but were unable to get any video, however. They got the camera a couple of times, but it seems as though the siskins would spook and fly off before they were able to record anything.

I was once told by someone originally from Anchorage that it was darker here (in Sitka) in the winter than in Anchorage. My first response was to say that didn’t make any sense – Sitka is significantly further south than Anchorage, and so has more hours of daylight in the winter. In discussing the subject further, I came to realize that length of daylight is not all there is to the equation. Sitka’s relatively warm winters with a relative lack of snow combined with persistent heavy cloud cover make for pretty gloomy conditions. When the snow does fall, things brighten up considerably – especially if the snowfall is followed by clear skies. Such was not the case on this early December day, however.

After nearly two months that seemed unseasonably warm and lacking in precipitation, this week has been a return to what I tend to expect of late winter and early spring weather. Monday’s cooler temperatures with heavy clouds and rain, were followed by a short reprieve in partly-cloudy Tuesday, but Wednesday temperatures dropped again, and we saw rain, snow, sleet, and maybe even a bit of hail broken up by brief patches of blue sky and attending sun.

Fairly easy to find around Sitka during spring and summer working their sap wells, Red-breasted Sapsucker abundance seems to drop in the fall and they are rarely reported from November through February along the road system. Most times when sapsuckers are seen, it is during periods with extended below freezing temperatures. At such times, they are most often found in forests with good south facing exposures (Totem Park being a good example). In the absence of any observations, it would be easy to imagine that these birds migrate south for warmer locales, and I suspect that is true for most of the birds that breed in the area. However, given the pattern of winter sightings over the years, it seems that some sapsuckers do spend the winter here, though apparently hiding somewhere they are not often noticed except during cold snaps.

I enjoy hiking the hills and mountains around Sitka, but over the past several years I have made it up relatively high only once or twice per winter. Somewhat surprisingly, on several of these hikes I have seen a sapsucker at moderate elevations (I’m guessing between 1000ft and 2000ft). Although this constitutes only a handful of observations, the fact that it occurred on a relatively high proportion of opportunities suggested that sapsuckers may be hanging out at mid-elevations throughout much of the winter, at least around Sitka.

Although my experiences finding sapsuckers led me to believe that they were likely to be spending winters in mid-elevation forests, I was puzzled because I could not figure out why they would prefer this habitat over lower elevations where conditions are less harsh. Adding to the mystery is that I do not remember seeing sapsuckers at mid-elevations much, if at all, during the spring and summer. I associate them almost exclusively with low elevations in forests near shorelines or valley bottoms, generally below <500 feet, and mostly closer to sea level than 500ft. A couple of weeks ago on my annual trek of Mt. Verstovia for the Christmas Bird Count, I once again found a Red-breasted Sapsucker working a tree at about 1500 feet or so. I watched the bird tapping at the well on the trunk of a moderate-sized Sitka Spruce, and for some reason I thought I remembered reading or hearing that getting sap to make maple syrup works best when nights are below freezing and days are above. I could not remember where I got this information (or if I had confused it somehow), so when I got home I took a look on-line. According to wikipedia’s article on maple syrup production, “Freezing nights and warm days are needed to induce sap flows. The change in temperature from above to below freezing causes water uptake from the soil, and temperatures above freezing cause a stem pressure to develop, which, along with gravity, causes sap to flow out of tapholes or other wounds in the stem or branches.”

The way I read this, sap flow seems to be a matter of physics more than anything special about the maple trees (though the same cannot be said of sugar content!). Freezing nights and warm days result in greater sap flow than consistently warm (or cold temperatures). This suggests a plausible reason that sapsuckers would prefer the mid-elevation forests over the warmer lowlands – at those middle elevations, temperatures are more often below freezing at night while warming sufficiently during the day to provide a more abundant food source for the birds.

It should not be too hard to test the temperature and sap-flow part of this hypothesis, a handful of ibuttons and a tap or two to collect sap ought to do it. (It would also be interesting to know whether the winter birds are individuals who also breed here, though that would be more challenging to determine, I suspect). Perhaps one of these winters I’ll give it a try, but in the meantime this is the best explanation I’ve been able to come up with for the somewhat unexpected behavior of Sitka area Red-breasted Sapsuckers in winter.

About a foot of snow covers the long muskeg below the Middle Sister.

I had heard this year was going to be an El Nino year, which seems to correspond to relatively mild winters in Sitka, so it was interesting to see winter season getting started relatively early this year, with snow beginning to fall last week. In fact, there is an El Nino developing in equatorial Pacific Ocean, but apparently in the Pacific Northwest, at least, El Nino impacts tend to be strongest later in winter.

I had ibuttons I wanted to place for a project on temperature variation I’m working on, so I took a couple of hours to hike up Indian River. There was not too much snow in the woods, but in the openings it was at least a foot deep. Temperatures are supposed to rise into the 40s this week, so the snow may not last long, however.

It was pretty quiet overall, but I did hear some Ravens and Golden-crowned Kinglets. I also saw a couple of Brown Creepers and a Varied Thrush. Lots of deer tracks, but I did not see any deer.

Peak 2890 is barely visible through the low clouds above the West Fork of Indian River Valley.

Red form of Fox Sparrow observed on Hillcrest Drive.

This winter there were several Fox Sparrows hanging around the neighborhood. Most winters Fox Sparrows are Rare at best, so it was unusual to see as many as 8, despite the cooler and snowier conditions that prevailed this year as compared to other years. Of particular interest to me was a red form (Taiga form in Sibley’s Guide) individual that I saw several times. Although the size, shape, and pattern of coloration is basically the same, the red form is not nearly as dark brown as the birds we typically see here. For comparison, I’ve included a picture of a more typical looking bird below.

Fox Sparrow

Swan Lake has remains almost completely frozen at the end of March. Since it first froze over in early December, it has not opened up significantly.

Although spring officially started last weekend, the winter weather continues to hold on, with snow falling most days last week and snow in the forecast through at least Friday.

Winter did not seem especially cold overall, but unlike many years, there was no extended period of above freezing temperatures. Swan Lake remains almost completely frozen, as it has since ice first formed by mid-December.

Despite the on-going wintery weather, there are signs of changing seasons. The herring have returned along with the many birds and marine mammals that feed on them, buds are swelling on many plants, and of course there is much more daylight. Last week I noticed a male robin that I suspect is an early migrant.

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.