The Humble Sparrow

Now a declining species in many parts of the UK Warwick is blessed with a decent sized population of the once ubiquitous House Sparrow (Passer domesticus). Many disregard this common bird as drab and boring but I find them charismatic and fascinating.

Their ever-present cheerful cheeps and squabbles fill our gardens all year long and this year I took a closer look when I began to notice a higher than usual incidence of mating.

 

Male Sparrow (c) M. Smith

 I first did a deep dive on the House Sparrow in 2012 when I was looking at comparing sparrow numbers in two different housing estates. I was looking to see if numbers were different between two adjacent estates, one built in the 1950’s and one in the 2000’s. My dataset was poor and the results were inconclusive, however, it did mean I read a lot about this bird.

The sparrow evolved in the Fertile Crescent (modern day Iraq and Iran) some 10,000 years ago. It spread widely with populations now found across the western Palearctic. In Britain, there is an estimated population of between 2,600,000 and 4,600,000 individuals which is believed to be an underestimate. This may seem a huge number but this is following a 45% decline in numbers between 1967 and 1999.

Female and Male Sparrow (c) M. Smith

Sparrows are mainly granivorous birds, only feeding their week-old young insects. This led the species being linked to agriculture and small villages where they nested in buildings. During the 19^th century, the species was having such an effect on crops that local Sparrow Clubs were set up in every parish in an attempt to eradicate them.

Declines in the cities seemed to be linked initially to the disappearance of the horse but later was more closely linked to the types of building and housing. In natural habitats, House Sparrows are gregarious colony breeders, building nests in caves or old trees. Early housing with poor roofing provided excellent artificial nest sites. Pre-1919 buildings have been found to be favoured the most but with the advent of plastic fascias and smaller gardens, suitable nest sites have been declining since the 1960’s and markedly more so since the 1980’s.

Sparrows keep in good condition by dust bathing, here on the canal towpath. (c) M. Smith

The sparrow has become dependent on mankind and its dwindling numbers are caused by an increase in pesticides reducing chick food, herbicides reducing adult food, haymaking occurring prior to seed set, reduced spillage of grain and better storage of grain and an increase in predators like Sparrowhawks and cats. In fact, studies on cat predation have shown that 28% of prey taken by cats were sparrows. Squirrels are also frequent nest raiders and will often chew through nest boxes to get the nestlings.

Breeding takes part from February onwards with as many as 4 broods a year possible. Unlike their distant cousin, the Dunnock (Hedge Sparrow) House Sparrows are mate faithful. Nest are built in holes in buildings or trees. Dominance in males is marked by the breadth of the black bib and chest and mating can be solicited by both the male and the female. I have seen this, this year. Early in the season, I watched a male pester a female for 20 minutes. Calling intently and flitting closer and closer until the female relented and yet weeks later I watched another female on the fence actively encouraging to mate. In both cases coupling was quick but repeated, I counted 8 copulation with a 3 minute period.

The act (c) M.Smith

Clutch sizes tend to be between 3 and 5 eggs which are incubated for 11-14 days with an 11-19 fledging period. Young birds emerge all looking very similar to the female with males developing their characteristic caps later in the season. The young birds continue to be supported by their parents for awhile and beg for food by rapidly flapping their wings and calling. Eventually these young will join packs of other fledgelings and adults in small flocks that squabble together loudly.

Two fledgelings being fed by an adult male (c) M. Smith