https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/house-sparrow/population-trends/
https://www.rspb.org.uk/our-work/conservation/projects/causes-of-population-decline-of-urban-house-sparrows/
Bird life international data zone 2023 map
http://datazone.birdlife.org/species/factsheet/house-sparrow-passer-domesticus