Crusty old Joe's

Kodiak Alaska Military History



The official web site of the Kodiak Military History Museum


THE NATURALIST
by Dave Evans

Blame it on the Weather
July 9, 2001

It's been interesting to be in Kodiak in a year when we had only half our usual June rainfall, and started experiencing the some of the hot dusty days of August in June and early July. Down in Michigan, over the past winter, I indulged myself in the occasional internet peek through the Kodiak AirportCam. No snow cover! At a time when Michigan snow removal contractors had more roof work than they could handle.

Temperature and moisture acting together can have some subtle biological effects on our surroundings here. I've been seeing some contrasts with my previous summers on the Island, and trying to speculate on the extent to which they're related to the unusual weather pattern for this year.

Some things seem about the same. I watch the snow patches gradually diminish on the peaks across Monashka Bay. Fort Abercrombie is again in full song as male birds set up territories. Especially for those species that thrive in the low visibility Sitka spruce and alder environment, sound is a much more reliable communication medium than vision as the birds flit among the alders and through the spruce groves. This is a good time to come out and listen to Abercrombie--hermit thrush trills and wheezes, varied thrush police whistles, and, of course, the golden-crowned sparrows plaintively calling, "Oh Dear Me." Things will quickly get quieter as the birds establish their territories, attract mates and settle down to some serious nesting.

One unfamiliar sight I encountered was hundreds of small caterpillars rappelling down on silk guylines from the spruce trees in the Park. In late evening when the sun strikes from a low angle, it's evident that some of our trees are fairly impressively shrouded with these silk threads. Park Headquarters has gotten calls asking for information about the caterpillars and the possible threat they pose to our spruces. What we're seeing are larvae of the spruce budworm moth. I suspect that during an "ordinary" weather year, the budworm population is held in check by natural enemies such as insect predators and parasites, and bacterial and fungus diseases. The dry climate of this year may well have stifled the population growth of some moisture-dependent enemies of the budworm, allowing the budworm population to take off unrestrained.

The caterpillars feed on the buds and the new growth of the spruces. Their guyline strategy allows them to descend farther down the tree canopy for new food, and even to be dispersed by the wind, parasailing off at the end of the silk lines. They'll eventually pupate in silken shelters, emerging after less than two weeks as small non-descript moths that live ten days or so, long enough to mate and lay eggs from which new caterpillars will hatch.

Spruce budworms are potentially serious tree defoliators, particularly if there are several outbreak years in a row. At this point, there's no particular cause for alarm on Kodiak, unless we experience the same population levels in the next several seasons. The budworm, by the way, is in no way related to the spruce bark beetle that is causing such damage on mainland Alaska.

Another place I'm seeing immediate effects of our unusual weather is the Fort Abercrombie wildflower meadow. Flowers are coming into bloom earlier, and if anything, more suddenly. The Nootka roses literally blew open overnight, suddenly creating a pink-dotted and fragrant expanse on the meadow. And their petals are already falling.

That's another aspect of this season: the blooming sequence in the meadow seems even more compressed than it has been in previous years. Later season flowers are already appearing. Yellow rattlebox and arnica are overlapping the last of the purple shooting stars, a linkage in time I'm just not used to seeing. Even the fireweed is impatiently jumping ahead of its normal place in the sequence, with flowers bursting forth at the bases of the spires. It's as though the seasonal progression is being run through almost frantically, and it leaves me wondering how our meadow is going to look by summer's end.

Kodiak's full of surprises, not the least being this season's weather. (Well, that, and the sight of a B-17 making a low-level flight down Monashka Bay.) I'll continue to be taken unaware by some of the complexities of the biological world around me. We're living in a special and beautiful environment here on the Island, and the even the unpredictability of the weather just adds to the fascination.


http://www.kadiak.org/naturalist/weather.html Updated 2001 August 20

www.ka diak.org