Spring is an exciting time to be in the field looking for birds. It is always fun to see birds that you have not seen since last summer.
To add to the enjoyment of spring birding is keeping track of the date that you first see a bird each spring.
Some of the first migrants to show each spring are shorebirds. They usually show about mid-April in small numbers and then increase to fairly impressive numbers. You have to spend a lot of time in the field to catch them as they are only in our valley a few days “staging.” Staging simply means they rest and feed, regain energy and then continue their flight north to Canada, Alaska and the Arctic Circle where they breed.
The fall migration south is much more relaxed, and an individual bird might “stage” for a week or more, before moving south to winter grounds.
Spring migration is short, only a couple of weeks, whereas fall migration can be spread out over a month or more. Spring migration is also the easiest time to identify shorebirds as they are in breeding plumage and their feathers are new and fresh. In the fall the feathers are worn, in non-breeding plumage and much more difficult to identify, though it is still fairly easy to do after much practice.
Shorebird is a general term for 62 species in North America. They are small to medium-size birds with thin bills and long legs. They typically forage on open shorelines and wet grasslands. Forty-one species have been found in Montana with 13 breeding in the state.
You have free articles remaining.
In the Upper Clark Fork River Valley at the Warm Springs Wildlife Management Area, south of Deer Lodge, I have observed 29 species. Of these, six breed locally and the remainder migrate farther north.
The first migrant species that I observed this year was the Greater yellowlegs. I actually saw one or two killdeer before the greater yellowlegs, but they occasionally over winter and might not have been a true migrant.
This year my first observation of the greater yellowlegs was on April 1 at the Job Corps Ponds. This was the earliest I have ever observed the species, and I have records going back 20 years. The average date for their spring arrival is April 16. The earliest previous record was April 10, so this year was nine days earlier than previous years. The reason for this would be pure speculation, but it is probably tied to the warmer than usual spring we have had. Northern migrants seem to sense the receding ice in the North and time their migration accordingly.
Of course, if there is a greater yellowlegs, there must be a lesser and there is. The two are easy to tell apart if they are together as the greater has a weight of 6 ounces, and the lesser averages 2.8 ounces. Thus, the length of the greater is 14 inches and the lesser is 10.5 inches. When they are found together one is obviously larger than the other. The identification is less obvious if you are only observing one. In this case you need to look at the bill. If the length of the bill is greater than the width of the head behind the bill it is a greater, if the length of the bill is the same or less than the width of the head, it is a lesser. The legs are long and bright yellow.
The breeding plumage is dark brown above and marbled with black and spangled with white flecks. The barring on the flanks is bold black on the white belly. Fall plumage is much more subdued, browner, and the contrast between marbled colors and white specks is nearly gone.
The browner-colored bird was photographed in late August and the darker bird was taken April 1, 2015. The difference in breeding and non-breeding plumage in these pictures is obvious.