House Sparrows
House sparrows in Devon
Jon Avon, November 2007
Devon’s House Sparrows continue to thrive in most places. They can be found in coastal towns, high moorland farmsteads, rural villages and city centres, yet House Sparrows are mostly overlooked and under-recorded. However, given the notable decline of their population in the UK, Devon’s House Sparrows are coming under closer scrutiny.
Devon’s population – stable at the moment!
In 2005, a survey of nesting House Sparrows was carried out by DBWPS members. A sample 108 breeding pairs on 60 properties across Devon were monitored and provided a baseline of information for future reference. The good news for House Sparrows was that 58% of members thought their local population was stable and a further 39% reported increasing numbers. Only 3% reported a decrease in House Sparrow populations.
A separate five-year study (2003–2007) in Kingsteignton, South Devon, has also revealed a broadly stable population. This study has indicated that the number of breeding adults was at its highest in 2003. Although the number of breeding adults decreased in 2004, the population has remained stable in 2005–2007. 
Nest sites & breeding habitats – the key to survival?
The 2005 survey produced some data regarding nest sites and nearby habitats. As expected, the results showed that nest sites were most frequently found in roof spaces, especially behind fascia boards. Nestboxes and House Martin nests were also well used.
Information on nearby breeding habitats was also recorded. This showed that 88% of nest sites had bird feeders nearby, 75% had newly planted hedges, 65% had old field boundary hedges, 65% had vegetable gardens/allotments, 58% had a lawn or field nearby and 52% had either an orchard or apple trees close by.
In 2003, the presence of hedgerows was identified as being a key factor in the breeding distribution of House Sparrows in the Kingsteignton study. The 2005 survey by DBWPS members also recorded hedges as a key habitat near nest sites; these were used by House Sparrows for feeding or as social gathering points. Hedgerow composition was recorded and revealed that the three most important components were ivy (50%), hawthorn (47%) and bramble (45%). Four other species were also noted as being present: honeysuckle (35%), holly (35%), blackthorn (33%) and hazel (33%).
From these two studies, it seems reasonable to conclude that House Sparrow populations are stable, and factors such as nearby bird feeders and hedgerows are significant factors in sustaining House Sparrow populations. The availability of bird feeders provides additional food for adult birds, while hedgerows are significant for nestlings in providing a natural food source (e.g. caterpillars).
Modern house design and improved home maintenance were the main reasons given in the DBWPS survey results where sites lacked nesting House Sparrows. The survey revealed that 15% of the nests monitored were in nestboxes. It is therefore feasible that nest site provision can be used to encourage House Sparrows if surrounding breeding habitats are available.
Further research into the value of hedges to House Sparrows should be encouraged. In the meantime it is important that hedges remain part of the urban environment in order to safeguard the future of breeding House Sparrows in Devon.
The House Sparrow year
Male House Sparrows begin territorial behaviour at nest sites from mid-October. Their noisy territorial chirping throughout the autumn mornings is often overlooked and resident breeding pairs are well established by the turn of the year.
The surveys mentioned above identified active nest building during February. This was noted from as early as 9 February (2005) and 14 February (2004). The peak nesting season is March to July, and most nest sites are abandoned by mid-August. In 2006, young House Sparrows were recorded in the nest on 28 August.
Breeding success remains difficult to establish due to lack of access to most nest sites. Nest boxes are an exception and can be monitored. A pair closely recorded in a nestbox as part of the Kingsteignton study produced an average of 9 young per year.
* 10 young from 3 broods in 2004
* 8 young from 2 broods in 2005
* 11 young from 3 broods in 2006
* 9 young from 2 broods in 2007
Given that the breeding population in Kingsteignton (2003–2007) is a minimum of 110 pairs, the potential exists for over 1,000 young sparrows to be produced each year. The survival of this juvenile population then becomes the key to sustaining a healthy population. Juvenile numbers peak in May–July and then disperse out of their natal areas. Adults undertake their post-breeding moult from late July to September and House Sparrows then remain in social groups until October when territorial behaviour begins again.
House Sparrow survival 2003–2007
The survival of young sparrows and adults is a factor requiring further exploration, and this information is likely to arise from ringing projects in Devon. Provisional survival rates based on ringing data in the Kingsteignton study show that in 2006 only seven out 100 sparrows ringed in 2003 were recaptured and only three of another 100 sparrows have been accounted for. This indicates either very poor survival rates or a notable dispersal from the ringing site. Ringing data also showed that the number of breeding adults decreased in 2004 but has remained stable during 2005–2007.
House Sparrows in Devon – the future
As the House Sparrow population in England is recognised as declining, the need to monitor and record Devon’s House Sparrow population is becoming more focused (populations in Scotland and Wales have increased since 1994 according to BBS). Fortunately, DBWPS members submitted a record number of House Sparrow records in 2006. Breeding sites, activity, flock sizes and other observations are becoming increasingly important and can now be compared with information gathered in the 2005 survey.
Ringers too are ringing more sparrows – 688 in 2006 (585 adults and 103pulli/nestlings). These are the highest annual House Sparrow totals recorded in Devon, which hopefully in due course will produce future data on survival or dispersal.
Hopefully, the combination of DBWPS members’ records and ringing information will enable a better understanding of Devon’s House Sparrows. In due course, conservation measures can be identified and implemented to ensure their population remains stable.
References:
Avon J. 2004. A study of House Sparrows in Kingsteignton, South Devon. Devon Bird Report 2003, 76: 259-261.
Avon J. 2007. DBWPS members’ survey of House Sparrow nest sites 2005 Devon Birds 60(1): 35-39.