Nesting Owls

Recently one of our dedicated volunteers snapped this photo of a great horned owl that is nesting on Norm's Island. The pair is not shy of people, as they have chosen to build their nest right above a main walking trail!
The great horned owl is one of the most common owls in the Americas. We first noticed the pair nesting on the island about a month ago, in early March. They use a variety of nest sites, and typically won't make their own nest, preferring instead to take over a nest made by another species. They will have one to five eggs at a time, and the young owls hatch in a fairly helpless condition. They are one of the earliest mating and nesting birds; the young owls should be hatching very soon. Meanwhile, other birds are still returning from a winter in the south and haven't began to build nests yet.
Stop by to visit us and see the owls soon!

Several Signs of Spring

There has been a flurry of activity in the Yellowstone River Valley as days become longer and the earth warms up. Recent weeks have brought the return of belted kingfishers, mountain bluebirds, great blue herons, sandhill cranes, and red-winged blackbirds. The painted turtles have woken up out of hibernation in the deep mud beneath Will's Marsh.

On a recent trip to look at schoolyard wildlife in Pryor, students found several grasshoppers. There are over 400 species of grasshoppers in the 17 western states. Grasshopper embryos suspend growth in the fall and enter a period of diapause (a dormant period). As the earth warms in the spring, the embroys continue growth and hatch out of their eggs. The diapause ends when soil temperatures reach an average of 50 - 55 degrees F. Grasshoppers undergo simple metamorphosis, as opposed to complete metamorphosis seen in butterflies and the majority of other insects. The insect that hatches out of the egg is called a nymph. It looks like the adult except that it is smaller and does not have wings. Young grasshoppers shed their skin as they grow from the nymph stage to adulthood.
Grasshoppers eat primarily grasses, though some species also eat forbs. They can be a destructive force on farmer's crops during years when the population swells. For a complete discussion of this fascinating insect, visit the USDA's online Field Guide to Common Western Grasshoppers.

Signs of spring

The sixty-five degree days in Billings this week have a lot of us fooled into thinking that winter is over. Even the animal world has come alive as if spring were really here. This afternoon we glimpsed the first painted turtle of the year swimming in Will's Marsh. Painted turtles hibernate at the bottom of the pond during winter. When they settle in to hibernate, their respiratory rate and pulse slow down significantly. Their body temperature drops to less than 50% of normal. Since they are not active and are not trying to keep their bodies warm, they don't burn up energy. Therefore they don't need much oxygen at all, and can get by on what they absorb from the water through specialized cells in their tails. They usually warm themselves back up in the spring when the weather is warm and their food supply again becomes plentiful. The turtle that was "awake" this afternoon may have a shock ahead as the temperature drops tomorrow. It is not clear whether the turtle will return to a state of hibernation, or if it will stay active, and try to get enough food to stay warm. Going into hibernation might seem like a better option, but keep in mind that it takes a LOT of energy to warm a body back up out of hibernation; it is energetically stressful. What do you think the turtle will do? We'll keep looking for him as the temperature dips back below freezing in the next few days.


Another surprising sighting on our pond this week was a beautiful male wood duck. This mid-sized duck normally arrives in Billings for the breeding season (though there are populations that live year-round in the western half of Montana). Wood ducks nest in tree cavities or boxes provided by humans. Like mallard ducks, wood ducks are dabbling ducks (as opposed to diving ducks). They feed mainly on seeds and invertebrates, and occupy a wide variety of habitats: creeks, rivers, overflow, bottomlands, swamps, marshes, beaver and farm ponds. For more information, visit the Cornell Lab of Ornithology's website.