An investigation in to the breeding biology and nestling diet of the House Sparrow in urban Britain Dr Kate Vincent, Dr Will Peach and Dr Jim Fowler

Methodology Fieldwork Key results Summary of findings

Methodology Record nesting success along gradient Investigate diet and invert. abundance L.C.C. - pollution data

Fieldwork Census/survey at 9 study sites No. boxes used = 100 [500+ chicks ringed] Monthly foraging obs. in 44 locations Provisioning watches - 55 completed Habitat mapping around used boxes Aphid abundance in home ranges Over-winter survival

Biometrics/Nesting success Weight Tarsus length Fat score Muscle score Faecal samples (400+) Colour ringing

Foraging Observations Does foraging change across season/area type? Initial visit recorded habitat type Made monthly visits to 44 transects Recorded no. of adults/juvs and habitat

Habitat Mapping Compare habitat around all used boxes Used 13 habitat category system Took radius of 70m around each nest ( gardens in suburbia)

Aphid abundance 0-50m & m from box selected 20 shrubs, 20 trees, 15 veg, 30 flowers scoring 0 to 3 (none to infested)

Key Results Diet of nestlings Productivity/nesting success Chick condition Habitat utilisation/selection

Diet composition (175 samples from 2001, 2002 & 2003) Thanks to Del Gruar for helping analyse samples

Nestling Diet Spiders, Aphids, Diptera & Beetles = 80% of all remains Beetles & Diptera prominent in April/May Aphids most prominent in June Ants most prominent in July/August

Nestling Diet Aphids - urban>suburban>rural broods Diptera - rural>suburban>urban broods  ants in broods that died  plant material during July/August & in broods that died

Productivity/nesting success No. fledged  late summer  No. fledged in home ranges with  grass/deciduous shrubs/trees &  concrete.  No. fledged from broods fed a plant-dominated diet High rate of chick starvation in June/July

 = 70% : 14 day chick period     IIIIIIIIIIII  = 20% : 14 day chick period IIII

Brood survival  Suburban nests = 75% (whole nest period)  Rural nests = 78% All habitats BTO (2002) = 96.5% Lack of food causing complete or partial brood failure –inadequate provision of food  poor quality habitat –provision of unsuitable food  nutritional deficiency/starvation

Productivity Mean no. fledged per attempt –suburban = 1.98BTO = 2.6 –rural = 2.37BTO = 2.9 Seasonal Productivity –4.21 young per year (suburban) –4.67 young per year (rural) –Oxford 1990s study = 5.68 productivity in this study is low due to high complete/partial brood failures

Chick condition chicks fed  beetle had higher body condition indices  grass, deciduous shrubs & trees,  concrete =  brood biomass  invert availability is sensitive to the habitat quality around nest  NO 2 levels =  brood mass at fledging –  post-fledging survival –fledging in  polluted areas = survival disadvantage

Habitat utilisation/selection 227 transects foraging observations most used = deciduous shrub least = evergreen/ornamental shrub Key habitats = deciduous shrubs, tilled land, grassy areas & trees Monthly effects  grass being intensively used in May but less in July In July: urban areas; concrete = 50%

Summary No. fledging & brood biomass  in home ranges with  grass/deciduous shrubs/trees  suggests invert. availability sensitive to habitat quality  fledged from broods fed a plant-dominated diet  evidence linking veg. dominated diet with complete brood failures  chick starvation during June/July not been reported before  NO 2 levels = lower brood mass at fledging

Conclusions nestling survival rate & no. young fledging are low links between; –poor habitat quality/insect availability/nestling diet/brood condition indicates direct effect of food limitation during the breeding season  causing  productivity in suburbia

Conclusions  productivity demographic mechanism causing decline  demographic model - test if productivity levels are low enough to cause declines  incorporated suburban & rural productivity levels and known survival rates (adult, first- year, post-fledge)  showed suburban productivity is low enough to cause 10% decline p.a

A BIG THANKYOU TO RSPB, EN & DMU Dr Will Peach & Dr Jim Fowler Derek Gruar (RSPB) Phil Grice (EN) All RSPB research assistants CJ Wildbird Foods (nestboxes) Householders that have nestboxes Denis Summers-Smith Ken Goodrich & LROS Leicester City Council My website: