Since it has been mentioned that Merlins taking mostly House Sparrows (no one has ever mentioned starlings that I know of) is hogwash, I thought it might be useful to look at the available data. I copy here Appendix 1 from the BNA Merlin account, which lists the results of 6 published studies of Merlin prey selection, specifically to contrast urban and rural nesting birds. You make your own conclusions.
The BNA account summarizes those and other studies as follows, "Most studies report specialization on one or two locally abundant species of small birds. Principal prey species characterized as: one of most abundant species in area, often foraging away from cover making it vulnerable to predation, and in 20-40 g weight range." That seems reasonable, and suggests that the primary food will indeed vary over space and time. Kevin ********************** Urban Rural S1 AU S2 AR MO AL House Sparrow (Passer domesticus) 63.6 75.7 64.5 - + - Horned Lark (Eremophila alpestris) 5.7 - 9.1 50.0 27.2 + Bohemian Waxwing (Bombycilla garrulus) 4.0 5.8 + - - - White-winged Crossbill (Loxia leucoptera) - 5.2 - - - - American Robin (Turdus migratorius) + + 4.3 - - - Chestnut-collared Longspur (Calcarius ornatus) + - - 37.0 + - Lark Bunting (Calamospiza melanocorys) - - - + 17.6 - Vesper Sparrow (Pooecetes gramineus) - - - + 12.6 - Mountain Bluebird (Sialia currucoides) - - + - 6.6 - Western Meadowlark (Sturnella neglecta) + - + + 4.2 - American Pipit (Anthus spinoletta) - - - - - 6.2 American Tree Sparrow (Spizella arborea) - - - - - 11.5 Fox Sparrow (Passerella iliaca) - - - - - 8.9 White-crowned Sparrow (Zonotrichia leucophrys) - - + - - 8.0 Dark-eyed Junco (Junco hyemalis) + + + - + 10.6 Snow Bunting (Plectrophenax nivalis) - - + - - 5.3 Lapland Longspur (Calcarius lapponicus) + - + - - 9.8 No of prey items 176 173 1332 2070 427 113 No of nests studied 3 5 65 46 20 4 Appendix 1. Principal prey species of breeding Merlins in urban vs. rural habitats in North America. Data presented as percentage of prey by number. Species that made up equal to or more than 4% of the total diet in a study are included in the table; + equals less than 4% of the diet. AL: Alaska (Laing 1985 ), AU: Edmonton and Fort Saskatchewan (James and Smith 1987 ), AR: Alberta (Hodson 1978 ), MO: Montana (Becker 1985 ), S1: Sasaktoon (Oliphant and McTaggart 1977 ), and S2: Saskatoon (Sodhi and Oliphant 1993 ). * Laing 1985 <http://bna.birds.cornell.edu/bna/species/044/articles/species/044/galleries/data/app1/species/044/biblio/bib053> * James and Smith 1987 <http://bna.birds.cornell.edu/bna/species/044/articles/species/044/galleries/data/app1/species/044/biblio/bib044> * Hodson 1978 <http://bna.birds.cornell.edu/bna/species/044/articles/species/044/galleries/data/app1/species/044/biblio/bib040> * Becker 1985 <http://bna.birds.cornell.edu/bna/species/044/articles/species/044/galleries/data/app1/species/044/biblio/bib005> * Oliphant and McTaggart 1977 <http://bna.birds.cornell.edu/bna/species/044/articles/species/044/galleries/data/app1/species/044/biblio/bib064> * Sodhi and Oliphant 1993 <http://bna.birds.cornell.edu/bna/species/044/articles/species/044/galleries/data/app1/species/044/biblio/bib098> -- Cayugabirds-L List Info: http://www.NortheastBirding.com/CayugabirdsWELCOME http://www.NortheastBirding.com/CayugabirdsRULES http://www.NortheastBirding.com/CayugabirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/Cayugabirds 3) http://birdingonthe.net/mailinglists/CAYU.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
