Streaked Horned Larks on the Reserve?

Horned Larks can be seen year round in the Reserve. Look for these inconspicuous birds as they walk slowly in the short grass or as they fly in big flocks low and fast across the grassy slopes. The only true lark native to North America, these  small, gray-brown, short-legged birds are found in open country all across North America. They breed from the arctic tundra of northern Alaska, south through the highlands of southern Mexico. Flocks numbering in the hundreds or thousands stream across the grasslands of eastern Merced County from October through March.  Small numbers of the resident subspecies, Eremophila alpestris actia certainly nest in the Reserve, but we've not yet confirmed this by discovering a nest.

The American Ornithologists Union recognizes 21 different Horned Lark subspecies ( a huge number!), with 15 occurring in western North America.  The subspecies is a taxonomic rank below that of species. The term refers to populations that are distinct morphologically (usually based on plumage color and size) and that are separated geographically. At 21 subspecies, the Horned Lark is probably unique among North American songbirds.

Color-banded Streaked Horned LarkDo the flocks that spend the winter in the Reserve consist of several different subspecies? Differences among subspecies are subtle at best, but it may be possible to make this distinction by careful observations using a spotting scope and binoculars. We now have an important conservation-related reason to make this effort!

The “Streaked” Horned Lark (Eremophila alpestris strigata) occurred historically between Oregon and British Columbia. Not so today. According to the National Audubon Society, “It has already been extirpated as a breeding species throughout much of its range including all of its former range in British Columbia, the San Juan Islands, the Northern Puget Trough, the Washington Coast north of Grays Harbor, the Oregon Coast, and the Rogue and Umpqua Valleys in Southwestern Oregon.” The current range includes the Willamette Valley, Columbia River Islands, Washington Coast, and South Puget Sound prairies. In fall 2013, the US Fish and Wildlife Service listed it as “Threatened.”

 
Reasons for Declines
There are many ongoing threats to the streaked horned lark’s habitat throughout its remaining range, from conversion of habitaty to agriculture and industry, loss of natural disturbance processes, such as fire and flooding (followed by encroachment of woody vegetation), invasion of coastal areas by nonnative beachgrasses, and incompatible management practices.  The continued loss and degradation of its scarce habitat could push the subspecies closer to rangewide extinction. Other threats include inbreeding depression, low reproductive success, and declining population size, which have been documented in the Puget lowlands population; without substantial efforts to stem the decline, larks may disappear from the Puget lowlands.  Threats from aircraft strikes and training activities at airports have placed lark populations at risk of further declines throughout the subspecies' range.

In winter, Horned Larks from all regions to our north head south for warmer climes. Could “Streaked” Horned Larks spend the winter in the Reserve?  Adrian Wolf, with the Center for Natural Lands Management, is asking us to help answer this question.

Adrian writes:
A large proportion of the South Puget Sound Horned Lark population has been monitored since 2006. The 2014 breeding season was extremely favorable for larks, and over 100 South Puget Sound nestlings received unique color bands. Many of these 3- to 5-month old birds will leave their breeding grounds and head south for the winter.

This is a request for observations of color-banded birds. Typically, the band combinations can only be read accurately with a spotting scope.  However, we are interested in the locations of any banded lark, even if you’re unable to read ANY of the bands or determine which legs they’re on. The particular arrangement of color bands on the tarsus, and placement of the color bands on each leg is crucial to identifying individuals, which will help us determine where these larks overwinter. All color-banded larks received a color band on top of the USFWS band on the right leg (either green, orange, white or purple) – this color identifies the birds natal site. The left leg may contain one or two color bands. If you observe a banded lark, please record the following information:

1. color combination on each respective leg
2.  date and location where you detected the bird (latitude and longitude coordinates would
be great)
3. a photograph, if possible

Please send observations to, Adrian Wolf, with the Center for Natural Lands Management (Email - awolf@cnlm.org).

The Reserve student team will be keeping a close look over the lark flocks this winter and with luck we may find some color banded birds from Puget Sound.

 

Date 
October 19, 2014