Tag Archives: nebraska

Sandhill Cranes on the Platte River

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For those of us living and working on the Central Platte River in Nebraska, the birds that signify spring’s arrival are much bigger than robins.  The annual arrival of sandhill cranes (we usually see the first ones around Valentine’s Day) lets us know that winter is coming to a close.  When the last crane leaves in early April, the first wildflowers in the prairies aren’t far behind.  This spring, the skies along the river are already criss-crossed with formations of flying cranes, intermixed with the ducks and geese of numerous species.  If you’ve never seen this unique phenomenon, you’re missing out on one of the greatest wildlife events in the world.  Come out to the Platte and start your spring right!

Every March, more than half a million sandhill cranes - the entire mid-continent population - converge on the Platte River in central Nebraska. Each bird spends about three weeks feeding and building fat reserves for the rest of their northern migration and the grueling nesting season.

In the evenings, the cranes come to the river itself to roost overnight. They favor broad channels with abundant bare sandbars where large groups of cranes can congregate in large noisy masses of up to 50,000 or more. As the sun starts to go down, wave upon wave of sandhill cranes drop gracefully into the river like so many floating dandelion seeds.

Not surprisingly, this wildlife spectacle draws bird watchers and nature enthusiasts from around the world. Crane watchers can drive rural roads to watch the cranes in the fields and meadows during the day, and stand on riverbank platforms (or reserve space in viewing blinds) to see them come to the river at night. Besides cranes, visitors to the Platte in the spring can also see millions of ducks, geese, and other waterbirds.

The cranes spend the night standing on bare sandbars or in shallow water. Their noisy calls eventually subside enough that they get some sleep, but it's rare that the entire group is quiet for long - and any disturbance (real or imagined) can quickly set the birds to calling and shuffling nervously about again.

In the morning, the cranes leave the river and head to nearby meadows and cornfields to feed. On some mornings, the birds seem reluctant to leave their roost, choosing instead to loaf, feed, and even bathe in the shallow water. Other mornings, a foraging eagle or roving coyote can push an entire roost site into flight simultaneously, and the sound of many thousands of wings creates a deafening noise.

Besides the important task of feeding, cranes spend much of their day - in meadows and along the river - socializing.

Courtship behavior is common during the day, and can include elaborate dances with much leaping and ducking of heads, as well as stick tossing.

As March comes to a close, cranes start heading north to breed - mostly in Canada, but also as far north as Siberia. They usually leave on sunny days with a nice south wind to carry them. Cranes can average 35 miles per hour and travel 200-300 miles per day (up to 500 with a good tailwind). In the fall, they pass through the Platte in small scattered groups (we usually just hear them flying overhead) - providing us with just a quick glimpse of them, but a reminder of what we'll see at the end of the coming long winter.

To learn more about how and where to see sandhill cranes in Nebraska, visit this or other websites.  If you come out, feel free to stop and stretch your legs at the hiking trails through our Platte River Prairies.

To see the best portfolio of sandhill crane photos in the world, visit Michael Forsberg’s website and look for his book “On Ancient Wings“.

Why are there stripes in my prairie restoration?

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The photo below was taken in September 2008.  It shows a long stripe passing through a restored prairie at the end of its 7th growing season.  The site was seeded with a drop spreader in November of 2001 (seed was broadcast on top  of soybean stubble shortly after harvest).  There are at least half a dozen of these stripes running through the prairie.  They vary slighly in width from a 1/2 meter to about 2 meters.

One of the stripes in the prairie restoration, delineated by the light colored seed heads of Canada wildrye inside the stripe and the reddish-colored big bluestem in the surrounding prairie. The site was planted in November 2001, and this photograph was taken in September 2008.

I’m confident that the stripes are a result of the way we seeded the site.  The drop spreaders we use (photo below) are named because they simply drop the seed straight out of the bottom of the spreader.  We load them up with seed and pull them behind ATVs, and try to overlap our passes slightly so we don’t create long skinny gaps that don’t get any seed.  In this case, I’m pretty sure we were a little sloppy and that these stripes are a result of not overlapping our passes very well – they line up exactly with the direction we were driving.  Because we were seeding on soybean stubble, it was hard to see the tire tracks from the previous pass, but we followed the rows as we planted so we’d at least go in a straight line.

The spreader we seeded the restoration with was similar to this one except it was a different brand and was slightly wider. There is an agitator inside and holes in the bottom, and the seed simply drops onto the ground as the spreader is pulled along.

As interesting as the visual effect is, what’s really intriguing to me is the exercise of trying to figure out why the stripes are still so obvious after 7 growing seasons (actually 9 growing seasons, because the stripes were still obvious in the fall of 2010).  We seeded this prairie with a light seeding rate (around 4lbs PLS per acre) but by its fourth growing season it was already dominated by perennial native plants.  Even if the strips we missed with the seeding didn’t get prairie seed that first year, they should have been getting seed rain from native plants (like big bluestem, which is all around them) by the 4th season.  Two or three seasons later, you’d expect that plants like big bluestem would be filling in those stripes – but it’s apparently not happening.

The stripes seem to be dominated primarily by Canada wildrye, with a smattering of other species like Canada goldenrod, annual sunflowers, and other annual weedy plants.  I’m assuming the wildrye colonized from plants that established adjacent to the stripes and subsequently dropped seed.  I can understand that.  But why didn’t other species colonize the same way?  Did the wildrye come in first and fill all of the open root spaces below ground, preventing other plants from colonizing?  Surely not.  The presence of annual plants in the stripes shows that there is space available for new colonizers.  In addition, wildrye was dominant in the rest of the prairie during the 3rd and 4th growing seasons but soon gave way to big bluestem and other longer-lived plants.  Why hasn’t that happened in the stripes?

It sure seems like there should be plenty of seed falling into the stripes from plants along the edges, but those seeds either aren’t falling, aren’t germinating, or aren’t surviving seedlinghood.  It’s like the stripes are in a sort of suspended animation – they developed into a 3rd season restored prairie and just stopped.

I’ve seen this kind of striping in some of our other prairies as well.  The most apparent is in a prairie that was seeded by Boy Scouts in 1997.  The Scouts walked back and forth across 1 acre squares we’d flagged out for them and threw seed as they walked.  That particular site apparently had a lot of Canada goldenrod in the soil when we planted prairie there because goldenrod established well across the whole prairie even though we put very little (if any) seed in our mix.  Most of that goldenrod has diminished and has given way to native grasses and other wildflowers, but there are stripes of goldenrod that have persisted – and they line up exactly with what must have been strips that the Scouts missed as they walked back and forth.  The stripes are starting to become less stark now (14 seasons after planting) but are still visible.

I’m very interested to hear from others who have seen this phenomenon.  I’d be even more interested to hear good rational explanations of why it happens.  I’m guessing it could be related to the difficulty people have experienced establishing diverse prairie restorations in old fields that have been idle for a couple of growing seasons.  I’ve always assumed that in the old field situation, a year or two of weed domination of the plant community resulted in such a high density of weed seeds in the soil that prairie plants couldn’t compete during early seedling establishment.  Maybe there’s something similar happening in the restored prairie stripes?  I’m really not sure.  I’m not worried by what’s happening (I like the heterogeneity and there aren’t any nasty weeds in the stripes).  I just don’t understand why it’s happening.

Help would be appreciated!  Thanks.