Bison Birds

The American Bison was historically called buffalo. That is a misnomer, as buffalo are actually old world species, but when European explorers first arrived to North America and encountered these huge animals, they named them something that they were familiar with.

 Bison once roamed in the millions, mostly across the wide open plains of middle and western North America. There is some historical record of them even in extreme southwestern Ontario, in the vicinity of what is now the Windsor area, as there were hundreds of hectares of tallgrass prairie before settlement. But that is the topic for another post.

Bison were well adapted to the cold, fierce winters of the mid-western part of the continent. Their winter coats were densely hairy, as this image shows, with the front end of the animal being the most densely hairy.

This was incredibly useful when facing the wind, which they typically did, to withstand the cold.

After the winter weather, they lost much of the dense hair towards the back of their bodies as shown next. Even so, the front end of the animal still retained a lot of dense hair. 

 Bison were always known to roam widely. The huge herds would have a home range of hundreds of thousands of square kilometres or more of open grassland. This next photo shows a single bull bison on a huge grassland at Grasslands National Park in extreme southern Saskatchewan. At the time I took this photo, in July, the bulls are usually well away from the cows and calves.

 It was said by early explorers that bison always moved into the wind as they were foraging, especially during the more inclement weather. This resulted in their long-range movements, and was advantageous in that a large herd of bison, numbering in the thousands, would eat off much of the short-grass prairie, but by keeping on the move, they would find new grasslands and give the areas they moved from, a chance to regenerate in time for a following season. Sometimes they would feed intensively on areas that had burned off via a prairie fire, and was regenerating with lots of tender fresh, green fodder.

Tallgrass Prairie National Preserve, OK

And that brings us to the Bison bird.

Most birds build their own nest, lay their eggs in it and raise their young.  This next photo shows a typical eastern grassland type bird nest. It is that of a Song Sparrow, and at the time of taking this photograph, it did not have a cowbird egg in it.

 But the Bison bird is a species that depends on following Bison, for the insects they disturb by their hooves during their movements as well as the seeds they break off of the grasses they are moving through. So the birds must follow the movements of these herds of Bison, and don't stay in one place for several weeks while they build a nest, lay eggs and feed the young to the point of the next generation being able to fend for themselves. No, these Bison Birds adapted so as to lay their eggs in the nests of other birds, with the new host raising the young of the Bison bird.

As time went on, Bison herds diminished considerably, and were at great risk due to the loss of foraging and roaming habitat due to settlement as well as the slaughter of millions of animals for their hides, or just for what was considered 'sport'. Large areas of the Bison's former habitat was turned into grazing lands for other animals, such as beef cattle. Probably the most best known breed at one point was the Texas Longhorn, but other breeds were eventually added. Hence the likely reason for the current name of this bird species. Texas Longhorns were aptly named, and came in various colours. They were the new grazer of the mid-western part of North America, some roaming free and others on large fenced grazing lands.

I'm sure that most readers will have caught on quite early in this post that the bird species I am referring to is none other than the Brown-headed Cowbird. 

male

female

 It is the only North American bird species that demonstrates this 'parasitic' behaviour, much to the dismay of some bird enthusiasts. I admit that I have had mixed feelings over the years, especially when I see a cowbird egg in the nest of a more 'desirable' species such as a Yellow Warbler, Prothontary Warbler, Wood Thrush, or some other species. All three of the aforementioned species have been, or are, considered a Species At Risk. 

Yellow Warbler

Not quite sure if this next image showing the young bird being fed is a cowbird or a young Yellow Warbler. It has some characteristics of being a cowbird, but would be easier to tell a few days after this photo was taken.

  Cowbirds are certainly not at any level of risk. In fact they often can be seen in huge flocks.

 

Presumably when these Bison birds were more or less confined to the wide open spaces of the mid-west, they had fewer potential host species to choose from. But as the eastern forests were cut down and opened up to a more agricultural landscape, these Bison birds adapted and became widespread throughout the east. In fact the cowbird is known to parasitize more than 220 species of birds in this way! As a result of the loss of forests, cowbirds became the dreaded edge species as they would regularly venture into a forest for 100-200 metres, and interior forest bird species nesting within that zone were heavily parasitized. Some ornithologists consider interior forest to be a minimum of 100 metres from any edge, whereas other specialists consider interior forest to be at least 200 metres from an open edge. Currently most forests in southwestern Ontario have been reduced to the extent that there is very little good quality interior forest to prevent cowbirds from entering and impacting the interior breeding bird species. Wood Thrush, now a Species At Risk, is usually an interior forest species, but sometimes can be found near the edges especially when proper interior forest is diminishing.

 This next photo shows an adult cowbird visiting the nest of a Yellow-breasted Chat, an extremely rare breeding bird in Ontario. 

I took this photo in about 1980. This was the first confirmed nesting of the Yellow-breasted Chat at Rondeau, and one of the few in all of Ontario. It was well away from any real forest edge, although a severe windstorm had caused a lot of blow-down which resulted in some shrubby habitat dominated by raspberry. It was great habitat for chats, but cowbirds also made it into the area. Fortunately the young chats in the nest were well along in their development so that if a cowbird laid an egg, it would not hatch before the chats would likely have fledged.

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A Prairie Highlight: Grasslands National Park

Those who know me fairly well, know that I like quiet, spacious and remote natural places. Therefore it will come as no surprise that Grasslands National Park, in the very southern part of Saskatchewan, is very appealing.

To many people, the prairie provinces conjure up images of fields of grain or canola waving in the wind and stretching to the horizon, and that is what does occur across much of the southern prairie provinces. Therefore to protect the real mixed-grass prairie landscape, in 1981 two sizable blocks of land about an hour south of Swift Current were set aside to form Grasslands National Park (GNP). (You can click on any of the following images to see a larger view.)

GNP holds a special place in our lives for another reason besides its quiet spaciousness. We had been here once before, slightly more than 32 years ago in June 1986.  We had been part way along on our westward trip when we got word that a baby boy was available to adopt so after a very brief visit to this new national park we returned home right way!

It was time for another visit, and this time we saw a bit more of it. The fact that it has been a little more developed than it was in 1986 made a difference as well, although the developments are such that there is little impact on the resource. The park encompasses about 350 square miles (907 sq km). We spent all of our time in the larger, west block.

A scenic trail drive for about 80 km takes one through various landscapes, with points of interest along the way. At times it seems rather bleak. But wait....what is that dark mound off in the distance?

 It turns out to be a Bison, one of more than 300 free-ranging individuals in parts of the park. Most of the herd was elsewhere, but this time of year the older bulls are off by themselves. They were very much a part of the natural landscape in past centuries, but had been extirpated many decades ago. A few were re-introduced in 2005 and the herd has done quite well.

 A telephoto lens is the best way to photograph them. For safety sake, it is recommended to stay 100 metres or more from any animal.

 This Bison was hanging out right in the vicinity of a threatened species: Black-tailed Prairie Dog. There are several colonies of this rodent here in GNP, and this is the most northerly location for this species in North America.

Their numbers have fluctuated greatly over the years, in part due to disease. The health of the prairie dog population has a direct effect on so many other species of threatened or endangered wildlife, including Burrowing Owl, Black-footed Ferret, Swift Fox, Ferruginous Hawks and Prairie Rattlesnakes.

We saw several Western Meadowlarks amongst the prairie dogs. This one had less yellow in the malar region than a 'good' western, but it was singing the western song.

 Also in the short grass were Horned Larks. At one point I noted a recent fledgling following its parent, begging for food.

The Scenic Trail crosses the Frenchman River in at least a couple of places, and that is where we were able to encounter a pair of Marbled Godwits.

Part way along the Scenic Trail is the Frenchman River campground. It is on the site of an old homestead, so even the little bit of development that occurs here is in a spot that was already disturbed from the homesteading days. It really is big sky country. This next photo shows the unserviced part of the campground, where we stayed. There were a few serviced lots nearby, but we didn't need the services and saved a few $$.

Across the way were some hills, and we watched a coyote roaming around sniffing bushes.

 A couple of Mule Deer came down from the hills and crossed the valley.

 Common Nighthawks were relatively common, even flying around in fairly broad daylight.

 Since there were no trees to roost in, it was interesting to see them roosting on fence poles, and were sometimes quite approachable. This next photo, although taken with a telephoto lens, was hardly cropped at all.

 The clouds were more visible with so much sky.

 As the sun set, the clouds took on quite a reddish-orange hue.

 GNP is apparently the darkest, Dark Sky Preserve in Canada. I had never tried night sky photography before, but got things set up and attempted it. I had to wait until about 11:30 p.m. to get some shots, and if I had waited another hour or so the results might have been better. I clearly need to refine my technique! The W-shaped constellation more or less in the centre is Cassiopeia.

Morning came early. This next photo was taken at about 5 a.m. local time.

 Mule Deer that had come down the night before were returning to the higher hills.

 A bird which appears to be a Vesper Sparrow was on a fence post. It wasn't singing and in the golden morning light, it looked a bit different.

The campground had Richardson's Ground Squirrels here and there.

 The campground office was about the only building around. Its construction was ideal for Barn Swallow nesting, and there were upwards of a dozen mud nests around it.

 Some had recently fledged.

 On the fences and elsewhere were birds such as Say's Phoebe....

 ....and Chestnut-collared Longspur.

 We eventually packed up and continued on our way around the Scenic Trail. A storm was brewing off to the north (severe weather, including tornadoes, occurred just north of the park that day) and we needed to be off. We did see several Sharp-tailed Grouse on the roadsides. Greater Sage Grouse are present in the park in very small numbers, but park staff were coy about any details.

 A Plain's Garter Snake was on the road enjoying a bit of early day sunlight.

 We saw the occasional Ferruginous Hawk atop a pole.

It was a short visit, but well worth the effort to get there even though it was a little out of the way. It is definitely on my priority list to return to, and spend a bit longer exploring the more remote parts of this fabulous national park.