Wyoming Migration Initiative's fundraising model profiled in High Country News Natural resources reporter Angus Thuermer profiled the many mule deer studies conducted by the Wyoming Migration Initiative and the Wyoming Cooperative Game and Fish Research Unit, with an emphasis on the outreach and private-public partnerships that fund our research. The article was originally published at the public policy news site WyoFile.
Migration Basics Although hummingbird migration is not well documented by large numbers of banding records, we do know a few facts, and we can draw logical inferences about some of the unknown areas.
This is currently the only way to identify individual hummingbirds. Species are studied by gathering data on large numbers of individuals. Each hummingbird species has its own migration strategy, and it's incorrect to think of "hummingbirds" as a single type of animal, all alike. This article will discuss Ruby-throated migration, because it's likely that more people see that species than all the others in North America combined, and its dynamics are similar to other species, although the dates and locations vary.
An exception is Anna's Hummingbird, which typically does not migrate but may wander up- and downslope following seasonal food resources. Banding studies suggest that individual birds may follow a set route year after year, often arriving at the same feeder on the same day.
We do not know if any individual bird follows the same route in both directions, and there are some indications that they do not. As with most of our migratory birds, hummingbirds apparently evolved to their present forms during the last ice age. They were and largely still are tropical birds, but as the great ice sheets retreated from North America, they gradually expanded their ranges to exploit rich temperate food resources and nesting space, filling unoccupied niches in the U.
S and southern Canada while evading intense Notes on season of migration to in the tropics. Some songbird species have adapted completely to our variable North American climates, in part by becoming vegetarians in winter, and don't migrate.
But hummingbirds are carnivores nectar is just the fuel to power their flycatching activityand depend on insects that are not abundant in subfreezing weather, so most of them must retreat back "home" to Central America in the winter or risk starvation.
A few Ruby-throated remain along the Gulf coast each winter instead of continuing to Central America, perhaps because they are too old or sick to make another trans-Gulf flight or too young from very late nests to have had time to grow fat and strong enough to migrate; their survival chances depend on the severity of each particular winter, and many perish in unusually cold years.
Another small population winters in the Outer Banks of North Carolina. Since hummingbirds lead solitary lives and neither live nor migrate in flocks, an individual bird may spend the winter anywhere in this range where the habitat is favorable, but probably returns to the same location each winter.
Ruby-throats begin moving north as early as January, and by the end of February they are at the northern coast of Yucatan, gorging on insects and spiders to add a thick layer of fat in preparation for flying to the U.
Some will skirt the Gulf of Mexico and follow the Texas coast north, while most apparently cross the Gulf, typically leaving at dusk for a nonstop flight of up to miles, which takes hours depending on the weather. Although hummingbirds may fly over water in company of mixed flocks of other bird species, they do not "hitchhike" on other birds.
Some hummingbirds land on offshore oil rigs or fishing boats to rest. Individual birds may make landfall anywhere between southern Texas and central Florida.
Before departing, each bird will have nearly doubled its weight, from about 3. Gulf coast, it may weigh only 2. It's also possible that a few Ruby-throats island-hop across the Caribbean and enter the U.
Males depart Yucatan first, followed about 10 days later by the first females. But the migration is spread over a three-month period, which prevents a catastrophic weather event from wiping out the entire species. This means that a few birds will arrive at any location very early the dots on the migration mapbut the bulk of the population will follow later, so you may not see your first hummingbird for several more weeks.
Each individual has its own internal map and schedule, and "your" birds may arrive early, late, or anywhere within a two-month span. Once in North America, migration proceeds at an average rate of about 20 miles per day, generally following the earliest blooming of flowers hummingbirds prefer.
The northern limit of this species coincides with that of the Yellow-bellied Sapsucker; if the earliest males arrive in Canada before sufficient flowers are blooming, they raid sapsucker wells for sugar, as well as eat insects caught in the sap.
The northward migration is complete by late May. Banding studies show that each bird tends to return every year to the same place it hatched, even visiting the same feeders.
See the Ruby-throated migration map for the species' range and earliest arrival dates. Southward Migration Unlike the Rufous and other hummingbirds of the western mountains, where freezing nights are common even in summer, Ruby-throats aren't well adapted to cold temperatures; they have a tough time below the mids Fand don't enter torpor as regularly as their western cousins to conserve energy.Season of Migration to the North and a great selection of similar Used, season migration north.
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Spring Light Goose Migration Update. April 30, The majority of light geese have moved into Canada. Late migrants will continue to move through the state over the next several days.
This concludes migration reports for the season. Some Notes on the Spring Migration Route. Notes on California Migration Key Trends, High Earners, and the Pacific Northwest. I have generally avoided doing lots of work on the big states . Therefore, in Season of Migration to the North, just as far as the west is engendered through refinement and order, so too has Mustafa Sa’eed subsumed the clichés of barbarism.
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