Vet Info-H • May–Aug 2023 • Vol 11 • No. 3 13 Wildlife Corner Bird migration is described as the regular movement of birds, each year, between breeding and wintering areas. Of the 10,000 known species of birds, roughly half of them migrate. Birds migrate to escape harsh conditions, explore places in search of food, and find environmental conditions conducive for breeding and rearing. Before the 1800s, bird migration left humans in awe; when birds migrated, people thought that the birds hibernated or “transformed” to other species, “grew on trees”, or flew to the moon. The reality of migration surfaced in 1822 when a bird shot in Germany had an arrow from Central Africa embedded across its neck, confirming a journey of thousands of miles. Since 1906, bird-watchers started leg-ringing the birds to understand migration. The arrival of the Pied Crested Cuckoo from Africa to India signals the onset of the monsoon season. The use of satellite tags has enabled humans to understand precisely how and where birds travel. A Godwit flying from Alaska to Australia (for 13,560 km) in 11 days, without a break, has set a new Guinness Record. Data from Frigate bird studies have demonstrated that birds sleep in “short bursts” of 12 seconds at a time, for up to 42 minutes a day on an average, in 10 days. Migrating birds are known to build significant body reserves before venturing on their journey. They also use the tailwinds blowing south. For direction, birds use the Sun, the stars, or an internal magnetic compass or a combination of all three, during their migratory journey. Bird migration serves as a source of nutrient transport, especially from seas to islands. Colonization of seabirds on volcanic-origin islands helps in nutrient transport, as the birds consume organisms from the sea, and their droppings on the island help in promoting and maintaining ecosystems on the nutrientdeficient islands. Bird migration is under threat due to human interventions in the landscape. For example, city lights confuse night fliers, wind turbines can kill birds, introducing wild and domestic predators at the nesting sites of migratory birds can reduce breeding success, and climate change can affect the timing and success of birds’ journeys. Sources: Pandey N, ed. Bird f lies from Alaska to Australia without stopping, breaks world record. https://www.ndtv.com/. Updated January 5, 2023. Accessed February 6, 2023. Salim A, Ripley SD. The Handbook of the Birds of India and Pakistan Together With Those of Bangladesh, Nepal, Bhutan and Ceylon. Vol 3. 2nd ed. Delhi, India: Oxford University Press; 1981:195. Bhattacharjee Y. Epic migrations. In: National Geographic Magazine. March 2018:34–59. Ali S. Bird Migration. London, UK: HarperCollins Publishers; 2010:194–197. The Science of Bird Migration
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