2021 in birding and ornithology

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See also 2020 in birding and ornithology, main events of 2021 and 2022 in birding and ornithology

The year 2021 in birding and ornithology.


New species

See also Bird species new to science described in the 2020s

Taxonomic developments



World listings

There are an estimated 50 billion wild birds, but only four species number in the billions and most species are rare. The birds with populations over one billion are house sparrow (Passer domesticus), European starling (Sturnus vulgaris), ring-billed gull (Larus delawarensis) and barn swallow (Hirundo rustica); 1180 species number less than 5000 birds each. Twenty-four years ago there was an estimate of 200 to 400 billion undomesticated birds, but the supposed decline is explained by differing methods, using data for more species from citizen science.[1]




  • The second European Breeding Bird Atlas (EBBA) was published, covering the presence or absence of 596 species, spannng 11 million square metres over 48 countries. Forest species are doing better than farmland birds and grassland, tundra and moorland species are also declining. On average species are spreading north at a rate of 1 km per year, although Bohemian waxwing (Bombycilla garrulus) are bucking the trend.



  • A young cinereous vulture (Aegypius monachus) has died of diclofenac poisoning in the Boumort National Hunting Reserve. The anti-inflammatory agent diclofenac, despite being banned in some Asian countries, has been approved for use in Spain and other European countries. Before being banned in Asia tens of millions of vultures are believed to have been killed by feeding on carcasses treated with the drug. The drug was approved because it was argued that cattle carcasses are disposed of differently in Europe than in Asia, and vultures would not be affected.[8]

North America


  • British Columbia (BC) temporarily halts logging in old-growth forests where the only three known northern spotted owl (Strix occidentalis caurina) live. Before the introduction of industrial logging it is estimated that there were up to 500 breeding pairs. There are currently twenty-nine owls (including nine breeding females) in outdoor aviaries near Vancouver and the target is 125 breeding pairs in the wild. As well as BC, the birds are found in northern California, Oregon and Washington and they are listed in the USA as a threatened species under the Endangered Species Act.[9]


  • With the collaboration of the Yurok and Redwood National Park, a captive breeding programme plans to reintroduce the California condor (Gymnogyps californianus) to northern California. Since reintroduction to south and central California, an estimated population of more than 300 free-flying birds have expanded into parts of Arizona, Baja California, and Utah.[10]
  • Since 1994, over 200 bald eagle (Haliaeetus leucocephalus) have died – all living near artificial lakes and all diagnosed with vacuolar myelinophathy, which causes holes in the spinal cord and brain. The eagles were eating, easy to catch, weak and uncoordinated fish and water birds. The weakened prey were associated with water-thyme (Elodea canadensis) which contained bromine, an element which, while not uncommon in nature, is rare in fresh water. The water-thyme leaves had almost 1000 times more bromide than was in the water. The source of bromide, in the lakes, is unknown.[11]
  • Between 2014 and 2018, 303 golden eagle and bald eagle were tested at the University of Georgia to determine their deaths. Of the 133 birds tested for the most common rat poison, anticoalulant rodenticide, 82% of the birds had it in their body and 4% died as a direct result. There was also a high-prevalence of highly toxic, second-generation anticoagulant rodenticides, which can remain active for months after ingestion.[12]


New Zealand

  • By spreading concoctions of bird pheromones around nest sites in the weeks before the arrival of the birds, research by Manaaki Whenua – Landcare Research shows that introduced predators can be fooled into ingnoring those nesting birds. Some mammals use olfaction to search for food and if the search is unrewarding they loose interest in the odur. The effect does wear off after approximately thirty days but, the birds produced 170% more chicks than those on untreated sites.[13]

South America


  1. Vaughan, Adam. "There are 50 billion wild birds on Earth – but four species dominate". NewScientist. Retrieved 25 May 2021.
  2. Blackman, Stuart (March 2021). "Mixed fortunes of Europe's breeding birds". BBC Wildlife. p. 26.
  3. "Covid-19: Exmouth bird tweet prompts rule-break fines for twitchers". BBC News. Archived from the original on 15 February 2021. Retrieved 15 February 2021.
  4. "Britain's third Northern Mockingbird found in Devon". BirdGuides. Archived from the original on 10 February 2021. Retrieved 15 February 2021.
  5. Fair, James (February 2021). "Gamebird licences introduced to preserve important wildlife sites". BBC Wildlife. p. 25.
  6. Birch, Simon (May 2021). "Curlew comeback". BBC Wildlife. p. 27.
  7. "Isles of Scilly: Egyptian vulture seen in UK for first time in 150 years". BBC News. Retrieved 15 June 2021.
  8. McKie, Robin (11 April 2021). "Rare European vultures being poisoned by livestock drug". The Observer. Retrieved 12 April 2021.
  9. McKenna, Carl (16 April 2021). "How Canada is trying to protect its last three spotted owls". The Guardian.
  10. Cistne, Sierra (27 March 2021). "Endangered condors return to northern California skies after nearly a century". Observer.
  11. Lesté-Lasserre, Christa (3 April 2021). "Lake toxin may be to blame for US eagle deaths". New Scientist. No. 3328. p. 20.
  12. Morse, Ian (17 April 2021). "American eagles falling foul of poison meant for rodents". New Scientist. No. 3330. p. 18.
  13. Blackman, Stuart (May 2021). "The misinformation game". BBC Wildlife. p. 25.