Sources : https://datazone.birdlife.org/species/factsheet/eurasian-siskin-spinus-spinus, https://en.wikipedia.org/wiki/Eurasian_siskin, https://www.fws.gov/species/eurasian-siskin-spinus-spinus, https://www.gbif.org, https://en.wikipedia.org/wiki/Spinus_(bird), https://collections.si.edu/search/detail/edanmdm:nmnhvz_4257726, https://agriculture.vic.gov.au/livestock-and-animals/animal-welfare-victoria/pocta-act-1986/victorian-codes-of-practice-for-animal-welfare/code-of-practice-for-the-housing-of-caged-birds, https://qfs.org.au/finch-info/aviary-design/, https://www.omlet.com.au/guide/finches_and_canaries/aviaries_and_bird_rooms, https://birdscoo.com/eurasian-siskin/, https://birdfact.com/birds/siskin, https://commons.wikimedia.org/w/index.php?curid=15279192, https://commons.wikimedia.org/w/index.php?curid=26572602, https://commons.wikimedia.org/w/index.php?curid=31560567, https://commons.wikimedia.org/w/index.php?curid=38618981, https://commons.wikimedia.org/w/index.php?curid=38618984, https://commons.wikimedia.org/w/index.php?curid=67675049, https://commons.wikimedia.org/w/index.php?curid=88419370, https://commons.wikimedia.org/w/index.php?curid=89484836, https://commons.wikimedia.org/w/index.php?curid=131666015, https://commons.wikimedia.org/w/index.php?curid=131666017