I’ve always wanted to visit this 42 square mile Utah state park that is connected to Salt Lake City by a long isthmus. And we hit a magnificent, sunny day with dramatic clouds over the lofty Wasatch mountains to drive around it.
Not the Minnesota lakes, but back to the 2021 cross-country adventure and the beautiful shoreline vistas of Lake Tahoe in the California Sierra Nevada mountains. Noting that this was primarily a birding adventure, nevertheless, this area provides some stunning scenery!
But the real excitement was on the lake itself, where an Osprey circled several times looking down as it flew. We hoped there might be some action if the bird spotted any fish below, and our patience in following its flights was rewarded with the following succession of images of its successful dive and capture — which I put together in a string from right to left.
We didn’t expect to see so many sea otters on our boat tour of the Elkhorn Slough in Monterey Bay. Several were in sight at any one time, almost every one with a youngster riding on top as the adult paddled along on its back.
Sea Otters were once very abundant in the coastal marshes and estuaries of western North America, but extensive hunting up until the early 1900s culled their numbers to just a couple thousand animals. Conservation efforts have increased their numbers somewhat, but they are only found in part of their original range. Sea Otters are an important part of the coastal ecosystem because they prey on the sea urchins that ravage the kelp beds and keep the herbivore numbers in check.
Sea Otters bring their prey to the surface, and consume it while floating on their backs. Naturally, some of the food drops onto their fur as they eat, so they continuously roll over while eating to dislodge food fragments. In addition, they meticulously groom their fur to keep it clean and fluffy (i.e., with lots of air pockets).
Otters breed at all times of the year, and pregnancy usually lasts about 4 months, but females can delay the implantation of the single embryo until conditions are best for the pup’s development. Pups stay with the mother 6-8 months, before venturing out on their own, when they are almost full adult size.
We had our own personal boat tour of the Elkhorn Slough, a 7-mile long tidal estuary on Monterey Bay that was the first estuarine sanctuary in the U.S. It began with a 60-acre purchase by The Nature Conservancy in 1971, and has grown to over 800 acres today. The entire 1.5 square mile marine reserve provides critical habitat for a variety of mammals (discussed in the next post), more than 300 species of birds, and a host of invertebrates and plant species on which the birds and mammals depend.
By some strange coincidence, a number of the bird species we saw on our boat tour had arranged themselves in groups of three — thus, I labeled the trios “the three amigos”. This is the time of year when bachelor groups of males break up and mated pairs are more often seen together, so seeing groups of three was somewhat odd.
We hiked through the cool, majestic big redwoods of the Forest of Nisene Marks in the Santa Cruz mountains the other day. I’m always impressed with the immense change in microclimate that these big trees produce, growing along the coast and trapping cool, moist air from the ocean each morning. The light filters through dense branches high above the trail, and only a few scattered sunbeams actually make it to the forest floor. So photography is a bit challenging under dim light conditions.
it juts right out of the ocean, a lone, huge boulder of a rock, standing 580 feet high. Morro Rock is one of the “nine sisters of San Luis Obispo County”, a series of volcanic plugs that rose into softer rock about 20 million years ago. The Rock is part of the state park and is closed to hikers and climbers so that Peregrine Falcons, Western Gulls, and Brandt’s Cormorants (among many other bird species) have a protected place to breed and raise their chicks.
We have been stopping along the California coast at various sites from San Diego to the Santa Cruz area to check out the shorebirds there. What a wealth of diversity of birds, and what a diversity of adaptations they exhibit, especially in their beaks.
Of course the beak is the primary tool for extracting food in shorebirds, so you would expect to find specialized structures to do that. For example:
Even closely related species (e.g., in the same genus) exhibit particular beak structures that allow them to specialize on certain food resources. Few species exhibit the extreme specialization of the Curlews, whose very long and decurved bill is designed to extract crabs and other soft-bodied invertebrates embedded deep in the wet sand or mud.
This has been a subject of interest every time I visit the California shore, and there is more information about this (and a video) in a previous post: “sharing the resources”
How would crystals (in particular, selenite crystals, a variety of gypsum), flies, and tiny little shorebirds called plovers possibly be related to each other? Well, this is a story of mutual benefits, with humans actually playing a positive role in the story for once.
Digging for Selenite crystals, a particular form of gypsum, is popular with crystal collectors, and so people come to the salt flats in Oklahoma to unearth some rare beauties to take home each year from April to October, the only times crystal harvesting is allowed on the Salt Plains National Wildlife Refuge.
The large holes left by excavating the crystals gradually fill with saline water and host a collection of microscopic organisms growing on the floor and sides of the holes. Along come brine flies that lay eggs on the surface of the water. When the eggs hatch, the larvae drop to the bottom and feed on the bacterial mats. After growing and pupating, adult flies hatch from their pupal cases and rise to the surface of the water to fly around searching for a mate to start the cycle all over again.
But, along comes the tiny shorebird, the Snowy Plover (along with a host of other shorebirds that might also nest in the salt flats) to pick off the adult flies as they emerge from the water before they can fly away.
Unfortunately for the Plovers, their required habitats for nesting are being taken over by beach development or other human recreational activities, and their nests are vulnerable to being crushed underfoot by hikers that wander into their nesting areas. But this unexpected benefit of having crystal harvesters (who are restricted in the areas they can dig) leave holes that can “grow” a food source for the plovers seems to be an ideal solution for nesting birds in Oklahoma.
As a general rule, complete competitors in the natural world cannot coexist, unless they divide up the resources somehow, by hunting in different areas or at different times, or specializing on slightly different food items in their diet.
On the wet prairies and marshes at Cheyenne Bottoms and Quivira National al Wildlife Refuge near Great Bend, Kansas, we saw several Short-eared Owls and and as many Northern Harriers, not only hunting in the same areas and habitats, but at the same time of day!
One study of niche overlap of Short-eared Owls and Northern Harriers in Utah found that their home ranges overlapped as much as 70%, but within their home range the two raptors hunted and nested in different parts. In addition, in this particular study, the owls tended to hunt most intensively in the mid-afternoon, while the hawks concentrated their hunting in the evening hours before dusk. So, even though the two raptors seem like complete competitors, they seem to have found a way to share the resources cooperatively…usually.
We made an unusual sighting today — a pair of Canada Geese defending their chosen nest site high in a canopy tree from passing Bald Eagles! What makes it unusual is that the geese had staked out a former eagle nest as their own, and were prepared to fight for it with a couple of immature and one adult Bald Eagle that flew by (the latter carrying a stick to add to its nest).
Fellow photographer Debbie was shocked that Canada Geese would nest anywhere but a raised hummock in or near a lake, and what were they doing so high up in this tree?
But I had seen this behavior from the geese before:
So what is up with these geese nesting in what we think of as un-goose-like nest sites?
Going back a couple of centuries, during the late 1800s and into Depression Era 1900s, the “giant” race of Canada Geese (the big ones we mostly see today) were almost completely extirpated from North America by unregulated hunting, egg collecting, and habitat destruction. They might have disappeared altogether if it weren’t for a tiny population discovered in Rochester, Minnesota, in the 1950s and some captive birds being bred in Boone County, Missouri. Some of these geese were used in a captive breeding program in the 1960s, and by 1981, 6,000 geese were released to the wild at 63 sites to repopulate the “giant” race of Canada Geese throughout North America. It’s hard to believe today with the huge numbers of these geese that roam fields, parks, and wetlands that the species was almost an ornithological footnote.
Now what does this history have to do with geese nesting in eagle nests and on osprey platforms? Observations of Canada Geese nesting high on bluffs above the Missouri River were recorded as early as the Lewis and Clark expedition of the river. But I think natural selection, especially the selection that resulted in culling their numbers almost to the point of extinction, could have played a part in explaining the flexibility of Canada Goose nesting behavior. The geese that survived the pogrom of overhunting were probably the ones that sought out remote places that were hard for hunters to get to, like cliff faces or raptor nests in tall trees. Survivors were probably the birds that used unpredictable and untraditional nesting places, not only to avoid being found, but because their traditional nesting sites had disappeared with human activity there. Today, Canada Geese nest in a variety of habitats, usually in wide open spaces with open fields of view: islands in rivers, the tops of beaver lodges and muskrat house, cliff faces, high nest platforms, and yes, raptor nests — even those of Eagles!