[Maine-birds] Re: Bobolinks

To add the historical perspective. Here is the excerpt from Palmer 1949 on Bobolink. (Hand transferred so excuse any possible typo you find) 

Bobolink

Dolichonyx oryzivorous(Linnaeus)

Summer resident, fairly common in settled areas throughout, including a few large islands, but diminishing somewhat in numbers in eastern counties; transient, common in spring and early fall. 

Spring. This species genearlly arrives in Cumberland County about May 9. The two earliest dates there are for May 5, 1906, at Westbrook (S. Hacker), and May 6 1928, at Cape Elizabeth (C. Mower). It has been seen as early as May 7, 1944 and May 11, 1947, by Mrs. P. Hannemann, at Hampden, Penobscot County, and May 13 at Presque Isle, by Chamberlain, although it generally arrives at the latter place from the 14th to 24th. Migration apparently ends in Southwestern Maine by June 4, but continues until the middle of the month in northern counties.

Fall. Migration begins by the second week in August, if not earlier. Spinney noted the species at Seguin as early as August 10 and 11, 1898. Most birds usually have departed by September 11, but one or more was seen on the 19th in Bowdoinham, Sagadahoc County, and one was caught by a cat on September 28, 1882, at White Head Island, Knox County(Norton), and one was seen as late as September 29, 1921, at Brunswick, Cumberland County, as reported by Walch(1926:58). 

Breeding. Of this species, Knight (1908b:339) wrote: "The nest is placed on the ground at the foot of a tuft or tussock of grass, sedge, or a small bush in a field or meadow. It is composed of fine grass and fine weed stems, lined with finer material of the same nature. The femal seems to do all the work of building and incubating, but the male does some little towards feeding the young." Data are at hand for ten sets of eggs, ranging from five to seven per clutch. The earliest date for a set, of six fresh, is June 2, 1939, at Brewer (Eckstorm), and the latest dates are: a set of five with incubation begun, on June 23, 1924, at Greene, Androscoggin County (Mendall). Young have left the nest as early as June 22, 1890, at Westbrook (Norton). Outside of Maine, the incubation period has been reported (Burns, 1915:285) as ten days. The Fledging period apparently is unrecorded. Only one brood is raised yearly.

Ecology. The Bobolink is a bird of damp meadows, or drier, rather uneven, fields where there is a good growth of clover or hay. About July 15, after the close of the breeding season, the birds gather in flocks on low ground about grain fields and on salt marshes along the coast. 

Remarks. In a letter to William Bartram, dated October 11, 1809, Wilson wrote that "the people of the District of Maine, of all of the New England States, and those who have lived on the river Illinois, declare that these birds breed there in vast numbers" (Ord, 1828: ci). There is other evidence, including data from older persons now living that this bird formerly was much more numerous than at present. Further, there have been many local changes in breeding distribution right up to the present time. Long ago, Hardy (1881) reported this species getting scarce in Brewer, but it is now present there in fair numbers. The overall picture in recent decades, however, is of a marked decline beginning perhaps about 1905, but which as lessened so that it has been relatively slight during the past decade. 

An item in the Portland Evening Express of June 5, 1931, under the heading of "Fifty Years Ago," reads as follows: "Many people in this vicinity are engaged in trapping bobolinks and linnets for the market."

In addition, Alexander Skutch noted in his book "Orioles, Blackbirds, and their Kin" in 1996, regarding their range "They appear to have been originally confined to the Northeast and have followed advancing agriculture westward almost to the Pacific coast; while in their eastern homeland they have become rarer as abandoned farms have reverted to woodlands or been covered by urban sprawl."

Also referenced was a tip for finding the nests discovered by James F. Wittenberger which was to "watch for the female to return to it in the dusk from her day's last absence for foraging.". I thought this might help those who have a field they are watching, work with the landowners to potentially avoid a few of the nests. 

Cheers, 

Rob O. 

On Tuesday, June 7, 2016 at 12:39:00 PM UTC-4, Noah Perlut wrote:

Hi all, I read the recent Bobolink comments and wanted to chime in.  I have a long-term study of Bobolinks and Savannah Sparrows nesting in agricultural fields in the Champlain Valley of Vermont.  Over the last 15 years we have monitored >2500 nests relative to the timing of hay harvest or rotational grazing.  A lot has come of this work--but a few things are important in this conversation.  First, Bobolinks decline between 2-3% in most states in New England.  So indeed, if you are comparing long-term numbers of birds, there probably are fewer birds in the fields you know so well.  Second, Bobolinks tend to prefer (yes prefer) fields that are mowed early and often. When they arrive in the spring these fields are green and lush.  They begin breeding in them 3-5 days earlier than in fields that are under a late-haying plan. 

Sarah is quite right that dairy farmers hay early for good reason--higher protein levels, which produces more milk from dairy cows.  Therefore, asking a dairy farmer to delay mowing is unfair to him/her, as it is economically impossible.  Given this constraint, we have worked hard to find a solution that balances early hay-harvest with bird needs--and with success.  Working with Vermont NRCS (Natural Resources Conservation Service), a branch of the USDA, we created a program for intensive dairy farms where we ask them to hay as absolutely early as possible in May.  All activities on these fields must be done by 31 May (but preferably earlier).  Once the field is mowed, they take the second harvest 65 days later (the typical interval between harvests is 35-40 days).  If a field is mowed early enough, this 65 day window is long enough for birds to recolonized the field, pair, build a nest, lay eggs, incubate, feed chicks, and feed fledglings.  Under this scheme, reproductive success is nearly as high as on field that are mowed after the breeding season.  Farmers that enroll in this program are compensated per acre enrolled for a three year period, and participants that we surveyed all stated that they were able to adjust their feeding programs to the changes in feed.  While this is a Vermont-specific program, a number of other states has created models around it.  I'm sure something similar could be successful in Maine.          

Even with this improved reproductive success, it is important to note that late-haying is the best scenario for these birds.  The persistence of grassland habitat in New England depends on continuing cow-based agriculture throughout the landscape.  Therefore, successful conservation can only happen through multiple strategies. If you have specific questions feel free to email me directly (npe...@une.edu). 

Enjoy those Bobolinks (and Savannah Sparrows, Meadowlarks, Grasshopper Sparrows, and if you are super lucky, Upland Sandpipers)!

noah perlut

On Friday, June 3, 2016 at 6:58:07 PM UTC-4, Geoffrey Ives wrote:

As usual we have multiple nesting pairs of bobolinks however, I'm pretty sure the counts are low. Last year they were higher - I counted up to 12 males at one time. This year the most I've seen at once are 4. Worried.

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