Wildlife
Dotterel, ptarmigan, snow bunting and golden eagle are among the breeding birds notified on the Cairngorms SSSI; mountain hare are widespread on the high ground. Britain's only free-ranging reindeer herd, reintroduced in 1952, ranges over the Cairngorms.
Season by season
| Season | Window | Conditions |
|---|---|---|
| Spring | April – May | Snow often still lies in the pass and on the plateau well into spring, so treat an early crossing as a winter day. The park-wide fire ban starts on 1 April. |
| Summer | June – August | The long daylight that makes a one-day traverse realistic. Still exposed: the MWIS forecast for the Cairngorms is written largely as warnings, and conditions on the pass are nothing like those in the glen. |
| Autumn | September – October | Shorter days, colder nights, and the first snow on the tops. The fire byelaw runs to 30 September. Plan the traverse around daylight, not around fitness. |
| Winter | November – March | A serious winter mountain route — frequently snow-bound, with avalanche-prone slopes on the flanking corries and no escape route from the middle of the pass. Full winter skills, ice axe and crampons. |