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RURAL CHANGES IMPACT. “These changes have reduced food availability, both of seeds, which sustain birds throughout the year, and of invertebrates, which are required by House Sparrows for rearing young.” https://www.britishbirds.co.uk/wp-content/uploads/article_files/V96/V96_N09/V96_N09_P439_446_A004.pdf View in LinkedIn

UNFINISHED TREND. “Today, the number of house sparrows in North America is only some 25 million, and the trend continues downward.” https://link.springer.com/chapter/10.1007/978-3-319-55396-2_5 View in LinkedIn

US SPARROW COLLAPSE. “After its introduction in the 1850s, the house sparrow quickly spread across North America, and 40 years later, it had colonized large parts of the continent. At its peak, the number could have touched half a billion. After that, the house sparrow population shrank in stages with periodic rapid decreases. In between, the numbers stabilized, before the decline continued. Lately, subpopulations, especially in the big cities, have all but collapsed.” https://lnkd.in/dGi32hq View in LinkedIn

EUROPEAN SPARROW COLLAPSE. “Dutch house sparrow (Passer domesticus) densities dropped by nearly 50% since the early 1980s, and similar collapses in population sizes have been reported across Europe.” https://lnkd.in/dyehfe7 View in LinkedIn

SPARROW MICROBIOTA. “We found urbanisation to be associated to lower microbiota species diversity, modifications in taxonomic composition and community structure, and changes in functional composition. Our results hence shed light on a hitherto little considered perspective, i.e. that the negative effects of urbanisation on city-dwelling organisms may extend to their microbiomes, causing potential dysbioses.” https://lnkd.in/dyfjm-b View in LinkedIn

HIGHLY SOCIAL BIRDS. “Reduction of colony size below some critical threshold may impair breeding behaviour to the extent that success declines, perhaps ultimately resulting in the disappearance of the colony...and increased dispersion of the colonies.” https://www.britishbirds.co.uk/wp-content/uploads/article_files/V96/V96_N09/V96_N09_P439_446_A004.pdf View in LinkedIn

COUNTRY FACTORS. “Factors proposed for the urban House Sparrow decline: predation by hawks and cats; increased bird competition for food; nesting site losses; pollution; lack of insect food; increased pesticide use; smaller colony sizes.” https://www.britishbirds.co.uk/wp-content/uploads/article_files/V96/V96_N09/V96_N09_P439_446_A004.pdf View in LinkedIn

TWO GROUPS. “There is no evidence of any significant interchange of House Sparrows between farmland and urban populations, and it is almost certain that the factors for the declines are largely unrelated.” https://www.britishbirds.co.uk/wp-content/uploads/article_files/V96/V96_N09/V96_N09_P439_446_A004.pdf View in LinkedIn

URBAN IMPACT. “In contrast, a gradual decline in urban centres continued, with little change for 50 years from the 1930s, before the urban population went into free-fall in the late 1980s or early 1990s. A gradual and continuing decline is probably also taking place in suburbs and small towns, though it has not yet become catastrophic.” https://www.britishbirds.co.uk/wp-content/uploads/article_files/V96/V96_N09/V96_N09_P439_446_A004.pdf View in LinkedIn

TWO DYNAMICS. “The situation in farmland appears to be quite distinct from that in urban centres. A major decline in farmland began in the late 1970s, but after a decrease of about 60% the population had stabilised by about 1995.” https://www.britishbirds.co.uk/wp-content/uploads/article_files/V96/V96_N09/V96_N09_P439_446_A004.pdf View in LinkedIn