Under the Microscope: The Spring Equinox

This time of year, as the last snow melts from yards and mountainsides, I always find myself getting excited for the spring equinox, which happens to be this Thursday, the 20th.  Although picnics and gardening may be weeks or even months off yet, the spring, or vernal, equinox marks the point in the year that daylight hours will start to become longer than nighttime hours.  No matter how many snowstorms happen between now and June, I take comfort in knowing the days are finally becoming longer than the cold winter nights had been.

Technically, the equinoxes occur when Earth’s orbit and axis tilt cause the Sun to pass directly over the equator, shining its light equally on the northern and southern hemispheres.  This has the effect of giving most places on Earth roughly 12 hours of daylight and 12 hours of night, which is where the term “equinox” comes from:  in Latin, “equi” means equal and “nox” means night, making it literally “equal night.”

The Equinoxes only happen twice per year, around March 20^th and September 22^nd, and mark the generally accepted beginnings of spring and autumn, respectively.  It’s easy to forget though that just as our northern hemisphere is slowly blooming into spring, the southern hemisphere will be celebrating the autumn harvest.  Another interesting fact:  the sun rises precisely from the east and sets precisely in the west on equinoxes.  

As the days lengthen the average temperature rises and nature is quick to take note.  Trees begin budding and grass shoots and wildflowers begin poking through the last of the slush.  Before too long insects are hatching, the birds are returning and larger wildlife are migrating out of their wintering grounds.  The number of daylight hours keeps on increasing until the summer solstice, the longest day of the year, which is on June 21^st this year.  The days then gradually get shorter through the autumnal equinox, up to the winter solstice on December 21, 2014. 

In Missoula, there is still a chill in the air and ice on the Clark Fork River’s banks.  But thanks to the passing of the equinox, summer’s warmth really can’t be too far off.

Friday Field Notes

"What? In Montana?!"

We expect that this will be the reaction of many of you to learning that a Scissor-tailed Flycatcher (Tyrannus forficatus) has been making its rounds in eastern Montana. This elegant, long-tailed bird, a member of the Tyrant Flycatcher family (better known around Montana for species such as the Western Wood-Peewee or Olive-sided Flycatcher), has been seen a number of times by birders near Pompey's Pillar National Monument in the past week. According to Montana Field Guide, the state's official database of species information and observations, there have only been 15 recorded observations of Scissor-tailed Flycatcher's in Montana!

Scissor-tailed Flycatcher. Pretty--and pretty weird in Montana.

The bird, whose summer breeding range is limited primarily to Texas and Oklahoma, is notorious for wandering far from its traditional range. With a body similar in size to an American Robin, its forked tail essentially doubles the bird's overall length. Scissor-tailed Flycatchers primarily use open, grassland habitats, including roadsides and agricultural lands. They are often seen perched on fence posts or power lines, scanning the ground for grasshoppers and crickets.

With migration season in full swing, this bird should be well on its way south towards Central America, making its appearance in Montana even more unusual. For birders and naturalists alike, this could be a once-in-a-lifetime opportunity to see a spectacular southern bird in our home state. So if you're around Billings this weekend and have a pair of binoculars, be sure to look for a Scissor-tailed Flycatcher. And if you should see it, be sure to let us know!

Happy Birding!

Friday Field Notes

Have you been wondering what’s going on around Missoula? Well, here’s a quick update on some natural history events occurring right in front of our eyes:

Fall Foliage

Although the gorgeous weather of late would have us believe that it’s still summer in western Montana, there are some signs that fall is on its way. Nighttime temperatures are dropping, the birds are stirring, and perhaps most noticeably, the leaves are beginning to turn. In just a few weeks, the Quaking Aspen and Western Larch trees that dot the mountainsides will shine gold, while the various maple trees found around town will fill the streets with shades of red and orange. Already, the larches have begun to turn a lighter green, indicating that it is only a matter of time before fall arrives.

Western Larch paint the hillsides gold

It is these vibrant colors and cooler temperatures that make fall one of the most pleasant times of the year in Montana. Indeed, fall gives us all a perfect excuse to get outside and put our naturalist skills to use.

Looking for ways to enjoy the turning of the seasons? Here’s some ideas:

•         Take a walk through Greenough Park. The towering cottonwoods and other deciduous trees that line Rattlesnake Creek will be putting on a show.
•         Go for a hike in the Rattlesnake National Recreation Area. Many trails in the Sawmill Gulch area climb high onto ridges that provide great views of the larch-covered hillsides.
•         Up for a challenge? Climb the steep slopes above the “M” to the top of Mount Sentinel for great views of fall foliage throughout the Missoula area!

Feathered Flyby

Like the turning of the leaves, the annual migration of birds from their summer breeding range to winter habitat is imminent! Birds are already exhibiting pre-migration behaviors indicative of this great journey. Various species of sparrows, warblers, and other woodland songbirds have gathered into mixed-species flocks, which provide members of the group with greater protection and increased feeding efficiency. Additionally, large groups of ducks and other waterfowl can be seen congregating on lakes and wetlands. Because of this, fall is an incredible time to go birding. The many wildlife refuges found in the region, particularly in the Mission and Bitterroot valleys, provide countless opportunities to observe migratory birds.

 Migration isn’t all about the movement of vast flocks of birds from northern latitudes to warmer climates, however. For many species of birds found in western Montana, migration consists of simply moving down in elevation - rather than in latitude – to escape the harsh conditions of winter. Many of the birds that summer in the region, often nesting high up in the mountains, winter low in valleys and in our backyards! As a result, the movement of birds to lower elevations during fall and winter presents a great opportunity to see rare and unique birds that are secretive and elusive the rest of the year.

Numerous species of finches, including Pine Grosbeaks, Cassin’s Finches, and the stunningly colored Evening Grosbeak, become common sights at backyard bird feeders. In addition, many corvids - such as Steller’s Jays, Gray Jays, and Clark’s Nutcrackers – move to lower elevations where food is more readily available. In the coming weeks, listen for unusual calls or sounds; it could be one of these birds settling in to the valley for winter!

A flock of Evening Grosbeaks invades a Missoula backyard, 2010. 

 So Missoulians, get ready for the many wonderful changes fall brings to our home!