Habitats and Seasons

Birdwatching Fundamentals 4 listed habitat as a step in identification, and Birdwatching Fundamentals 5 noted that the dawn chorus peaks in spring. This chapter takes up both ideas: where to look, and how the year changes what you find. Most of its sourced material is about migration, because that is where the year most visibly reshapes the birds in front of you.

Habitat: Where to Look

The articles I read do not give a general list of habitats, so this section is my own general knowledge and should be checked against a regional guide (check). Different places hold different birds: woodland, open farmland, wetlands and shorelines, moorland and mountains, towns and gardens. Chapter 4's method uses habitat to remove unlikely options, so a duck on a pond is a likelier suggestion than a woodland songbird on open water.

Why Birds Migrate

Wikipedia's Bird migration article defines migration as "a seasonal movement of some birds between breeding and wintering grounds that occurs twice a year". Food is the main driver, according to the article; some hummingbirds skip migration if they are fed through winter. Longer northern summer days give breeding birds more time to feed their young, which allows larger clutches. These benefits offset the stress, energy cost and risk of travel.

Kinds of Movement

Records and Routes

The article says many populations travel along a flyway, with routes that often follow mountain ranges, coastlines or rivers and may use updrafts and wind patterns. Outbound and return routes are often different. It gives these records:

• Arctic tern: "the longest-distance migration of any bird"; one tracked bird covered about 96,000 km in 10 months.
• Bar-tailed godwit: some birds make "the longest known non-stop flight of any migrant", about 11,000 km from Alaska to New Zealand, after storing 55% of body weight as fat.
• Bar-headed goose: GPS tracking recorded flights up to 6,540 m (21,460 ft) over the Himalayas.
• Geese in V formation: may save 12–20% of the energy of flying alone.

Wikipedia's Arctic tern article gives more detail: the shortest distance between its breeding and wintering areas is 19,000 km; a 2010 study of 11 birds from Iceland and Greenland found an average of about 70,900 km a year, with a maximum of 81,600 km; and a Farne Islands bird tagged "G82" covered 96,000 km in ten months in a 2015–2017 study. A chick ringed on the Farne Islands in 1982 reached Melbourne in about three months, more than 22,000 km.

How Birds Find Their Way, and When They Go

The article says birds use a mix of cues: the Sun and stars, the Earth's magnetic field, visual landmarks, smell and learned mental maps. Young birds on a first migration head in the right direction using magnetic cues and learn landmarks through experience. Day length is the primary physiological cue. Caged birds show restlessness (Zugunruhe) at the usual migration time, which suggests internal annual programs.

Reading the Year as a Watcher

This table is my own general summary, not from the articles, and the details differ by country and species (check).

Not Yet Verified, and Sources

• Sources. Bird migration: the first 100,000 of about 207,000 characters were read, via a summary by the fetch tool; the Arctic tern article was also summarised.
• Not in the articles. The habitat section and the season table (my own general knowledge, check).
• Unresolved. The tern lifetime-distance figure does not match simple multiplication (see the warning box).
• Not used. The Bird migration page also gave a 2026 assessment about the share of migratory species in decline; I did not use it because I could not read its context.

Exercises