February 4-10, 2024

Bracketed by sun

Twisp on a sunny, late winter day. Photo by David Lukas

This has been another week with more of the same gray, drizzly weather—but bracketed by two gloriously warm and sunny days.

Week in Review

The warm, sunny days that started and ended this week highlight the risks that plants and animals face as they gauge when to transition from their winter phase into their spring phase.

early plant buds
A few trees at Pearrygin Lake are starting to produce buds. Photo by David Lukas

On a walk at Pearrygin Lake, we heard one courageous treefrog calling at the edge of the frozen lake, and I noticed a number of plants starting to green up and produce buds. This made sense on a day that felt like a perfect spring day, but the next morning it was snowing, and we went straight into another week of winter weather!

The clues are faint, but bitterbrush is starting to green up. Photo by David Lukas

Despite this setback, it's undeniable that there's a subtle shift taking place. Grasses and small plants on the ground are producing new leaves, a few insects are flying around, and birds are beginning to sing.

pine grosbeak
Pine grosbeaks are still active at Pearrygin Lake. Photo by David Lukas

House finches and American goldfinches in the tree over our bird feeder are now spending long periods of time vigorously chirping and singing. On February 5, we heard red-winged blackbirds singing for the first time this winter, and they've been singing every day since.

red-winged blackbirds
Red-winged blackbirds singing together, but not yet defending territories, on February 6. Photo by David Lukas

red-winged blackbird
One lonely blackbird trying to defend a territory months before the breeding season begins. Photo by David Lukas

It's been at least a month since I last saw Canada geese, but a pair flew around Big Twin Lake on February 4 and the same day I spotted the first immature northern shrike I've seen all winter.

Canada geese
A pair of early Canada geese checking out Big Twin Lake. Photo by David Lukas

immature northern shrike
Immature northern shrikes can be recognized by the warm colors on their heads. Photo by David Lukas

In other words, it's time to start paying attention to the changing seasons. We could definitely get another round of cold winter weather—and the Farmer's Almanac is predicting this—but momentum is shifting towards spring and things are going to start getting exciting over the next month or two.

Over the past year, the effort of producing this newsletter has been sustained by your generous subscriptions and I am so thankful for your support. If you want to help with this effort, you can sign up for a paid subscription, or make a donation in any amount using the link below.

Observation of the Week: Bioprecipitation Feedback Cycle

The earth and sky are always dynamically interacting! Photo by David Lukas

The bioprecipitation feedback cycle is a fancy way of explaining how bacteria produce rain and snow in clouds. I wrote in detail about this topic in my Lukas Guides newsletter this week (click here to read this article), but here's a brief snapshot of this fascinating story.

You might think that raindrops and snowflakes just magically fall from the sky, but this only happens because bacteria floating in the air have a unique ability to promote the formation of ice crystals that become heavy enough to start falling.

Ice crystals fall as snowflakes when the air is cold enough. Photo by David Lukas

If the air remains cold these ice crystals continue falling as snowflakes, but if the air is warm enough these crystals turn into raindrops as they fall.

water puddle
Both snow and rain result from bacteria in clouds. Photo by David Lukas

These bacteria are a critical part of the earth's atmospheric cycles because they produce the rain (and snow) that allow plants to green up and produce flowers. In fact, the bacteria evolved 150 million years ago, around the same time that flowering plants first appeared. Ultimately, the lives of flowering plants and these bacteria are intricately interwoven.

bioprecipation feedback cycle

Where this story gets really fascinating is when you look at what the bacteria do when they get back on the ground...but that's the topic of this week's Lukas Guides newsletter.