Britain's Magpie Parliament 



These crowlike birds hold boisterous sessions every year in early spring 



by Tim Birkhead 



On the outskirts of Sheffield, one of 

 Britain's largest industrial cities, lies the 

 Rivelin Valley, a microcosm of traditional 

 rural England. Woodland borders the 

 stream that flows through the valley floor, 

 and cattle and horses graze in the tree-dot- 

 ted fields of the valley and surrounding 

 hillsides. This region has long been home 

 to a thriving population of black-billed 

 magpies, a species that farmers and game- 

 keepers invariably regard as pests. The 

 British naturalist Charles Dixon wrote in 

 1900 that "nowhere else in our experience 

 have the magpies been allowed to live in 

 such peace as they enjoyed in this roman- 

 tic valley." 



Magpies still inhabit the Rivelin Valley, 

 where I have studied their breeding behav- 

 ior for the past fifteen years. These color- 

 ful, long-tailed relatives of crows first cap- 

 tured my attention when I was a schoolboy 

 birder. Magpies are hard to miss. Beauti- 

 fully plumaged, large, loud, and social, 

 they are renowned for flieir noisy "cere- 

 monial gatherings." More than a hundred 

 years ago, these aggregations were 

 brought to Darwin's attention by his 

 cousin WilUam Darwin Fox, the rector of 

 Delamere, who referred to them as "the 

 great magpie marriage." Darwin later used 

 this information in The Descent of Man 

 and Selection in Relation to Sex: 



They [the magpies] had the habit very early 

 in the spring of assembling at particular 

 spots, where they could be seen in flocks, 

 chattering, sometimes fighting, bustling and 

 flying about the trees. The whole affair was 

 evidently considered by the birds as of the 

 highest importance. Shortly after the meet- 

 ing they all separated, and were then ob- 

 served by Mr. Fox and others to be paired 

 for the season. 



I had long been intrigued by these cere- 

 monial gatherings, but I had a gut feeling 

 that Darwin was wrong in thinking them 

 to be mating ceremonies. By marking sev- 

 eral hundred birds witii unique combina- 

 tions of color bands and following them 

 through the course of flieir fives, I was able 

 to discover the true function of the yearly 

 gatherings. 



Black-billed magpies are found in a va- 

 riety of habitats across much of the North- 



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