Behaviour · BEH·06
Raven Nesting Behaviour
Sites, season, pair bonds, and breeding biology
[science] Common Ravens nest on cliff ledges and tall trees, beginning as early as February in northern latitudes — unusually early for a corvid. The nest is a large stick platform reused annually. Clutch: 3–7 eggs. Incubation: 20–21 days (female only). Fledging: 35–42 days. Young remain dependent on parents for several months post-fledging.
Nest Sites
[science] Ravens show strong preference for elevated, inaccessible nest sites:
- Cliff ledges: The primary natural preference; cliff faces provide protection from predators and stable thermal conditions
- Tall trees: Conifers and large deciduous trees; ravens build in the upper canopy
- Pylons and transmission towers: Increasingly used in many parts of range; electrically problematic and sometimes managed
- Bridges, buildings, quarry faces: Opportunistic use of human structures
Nest site fidelity is high — pairs typically return to the same site year after year, with one study at a Welsh cliff site documenting the same location used for over 30 years (Dare 1986, cited in Boarman & Heinrich 1999). Some pairs maintain two or more alternate sites and switch between them.1
Nest Structure
[science]
- Outer structure: Large platform of sticks and branches — can reach 60–120 cm diameter after years of annual additions
- Inner cup: Lined with softer material — wool, hair, bark strips, dry grass, moss, feathers
- Construction: Both sexes build; female does most of the lining
- Time: Construction takes 1–3 weeks; re-lining of an existing nest takes less time
The accumulated size of old nests can be extraordinary. Reused annually, some raven nests weigh tens of kilograms. The mass can occasionally cause structural problems on pylons.1,2
Breeding Season and Timing
[science] Ravens are early breeders relative to most birds at the same latitude:
- Nest building: January–February in UK and northern Europe; similar timing in North America
- Egg laying: February–April (latitude-dependent)
- Incubation: 20–21 days; female incubates, male provisiones her
- Hatching: March–May
- Fledging: 35–42 days after hatching
- Post-fledging dependence: Several months — young ravens follow parents and beg food
Early nesting means chicks are present in cold weather, requiring significant brooding. The adaptive advantage is that chicks fledge in late spring/early summer when food is becoming abundant. By the time winter arrives, young birds are independent.2
Pair Bonds and Mate Fidelity
[science] Ravens form long-term pair bonds, typically maintained until a partner dies:
- Pairs defend territories year-round, not just during breeding
- Pair bond formation involves extended courtship — aerial displays, bill-to-bill contact, mutual preening, and food-sharing
- Divorce (voluntary pair dissolution while both partners survive) is rare but documented
- Widowed ravens typically re-pair with floater birds
Both parents feed nestlings and fledglings, though the division of labour shifts: the male does most provisioning while the female broods. As chicks grow, both parents hunt and forage for the family.2,3
Breeding Success and Chick Survival
[science] Long-term studies in Wales (Dare; cited in Boarman & Heinrich 1999) and North America provide breeding success data:
- Mean clutch size: approximately 4–5 eggs in well-studied populations
- Hatching success: variable; infertility and early nest failure reduce it
- Fledging success: typically 1–3 chicks per successful nest
- First-year mortality: high — most deaths in the raven population occur before age 2
- Age at first breeding: typically 3–4 years; some individuals breed at 2
Breeding pairs that hold good territories in productive habitats (e.g., near landfills or carcass-rich rangelands) show consistently higher chick output than pairs in marginal habitats.2
Non-breeding Birds
[science] A large proportion of the raven population in any area consists of non-breeding "floaters" — subadult and young adult birds that have not yet established territories:
- These birds form communal roosts and may number in the hundreds at good food sources
- They probe territorial pair boundaries and attempt to access territory resources
- They eventually acquire territories by inheriting vacant ones, displacing weakened residents, or establishing new territories at the periphery
The two-tier social system (territorial pairs + floating non-breeders) is a key feature of Common Raven population ecology and explains much of the behaviour documented at large carcasses and food sources.2,3
Frequently Asked Questions
Where do ravens nest?
Common Ravens prefer cliff ledges as nesting sites — high, inaccessible locations with good visibility. They also use tall trees, pylons, bridges, and buildings. The nest is a large platform of sticks lined with wool, hair, and plant material. Ravens often reuse the same nest site for many years, adding material annually.
When do ravens nest?
In the northern hemisphere, Common Ravens begin nest building as early as January and lay eggs from February to April, depending on latitude. Early nesting is unusual among corvids and may relate to the need for chicks to fledge before summer when food demand is highest. Southern populations breed later.
Sources
- Madge, S. & Burn, H. (1994). Crows and Jays. Christopher Helm. — nest structure, timing, and breeding biology.
- Boarman, W. I. & Heinrich, B. (1999). Common Raven (Corvus corax). In A. Poole & F. Gill (Eds.), The Birds of North America, No. 476. — comprehensive breeding data.
- Heinrich, B. (1989). Ravens in Winter. Summit Books. — pair bonds, territory, non-breeding floaters.
[science] field-guide and species-account data