Hydroprogne caspia
Drawn from open occurrence records in and around Redwood National and State Parks, aggregated onto a 25 km grid. A cell is matched by its centre, which can sit up to 16 km outside the boundary, so this covers the surrounding country too.
Occurrence records measure where people looked and found something, which is not the same as where the animal is. This is a relative likelihood, not a probability.
Records exist for March, April, May, June, July, August, September, October and December, with the widest coverage in March, April, May, June, July, August, September, October and December. A quiet month can mean the animal was absent, or that nobody was looking.
A grid cell is a square of the map, not a sighting: 1 square of 25 km carry records for Caspian Tern in and around Redwood National and State Parks, and the 2,373 records behind them were collected by other people and published openly. Nothing here counts animals, and a place with more records is not always a place with more animals.
West Coast National Park and Table Mountain National Park are the two atlas places where the Caspian Tern is recorded. Its records concentrate in the United States, Canada, Taiwan, Australia, and Mexico. The atlas holds about 1.1 million records of the bird across 17 countries, and the map highlights where these records gather.
Of the 13 species with an atlas page recorded in and around Redwood National and State Parks, the Caspian Tern is the 8th most recorded.
The full atlas page, and everywhere else it is recorded