Mammals
1,405 Bos observations — the 3rd most-recorded species overall, behind only Buteo buteo and Sitta europaea. One of the 'Big Five' of the Bos (with otter, raven, badger, and kingfisher per various counts). Red squirrel: native, not displaced here by grey squirrel (which has never colonised mainland NL).

| Total observations in the Bos | 1,405 |
| First recorded | 1967-12-15 |
| Last recorded | 2026-05-22 |
| Max rarity tier | 2 — uncommon |
Data derived from 136,107 waarneming.nl observations at location 5013 (Amsterdamse Bos), scraped May 2026. Bos-context text: manually composed from the Bosplan 2020–2030, amsterdamsebos.nl, and the existing Het Onzichtbare Zichtbaar dossiers.