Red-tailed Hawks

of Southern California

Photo credit: Pete Bloom (all rights reserved)

  • The most common large raptor in southwestern California.

  • Can nest in almost any habitat where an adequate structure exists to support a nest (i.e. trees, power towers, cliffs, etc.).

  • Home ranges are typically about 1 – 1 ½ square miles within coastal California areas.

  • Prey usually consists of Audubon's cottontail, California ground squirrel, dusky-footed woodrat, Botta’s pocket gopher and gopher snake.

  • Typically lays eggs from late February through late March. Incubation lasts about 30 days with young fledging at 6.5 weeks of age.

  • Young hawks may disperse up to 1,000 miles from the nest site, however most return to breed within 20 miles of where they fledge.

  • The oldest known Red-tailed Hawk in southern California survived 28 years.

RESEARCH

Northward summer migration of Red-tailed Hawks fledged from southern latitudes. Journal of Raptor Research (2015)

  • A significant majority of fledgling Red-tailed hawks from southwestern California migrate north.

  • Migration is initiated during the summer.

  • They travel substantial distances (Range = 380–1400 km).

  • They generally spend the summer in the Central Valley or in the Great Basin Desert.

  • Migration occurs annually four times over four years, then they become a resident.

RESULTS

  • Northbound Migration began as early as 25 June and as late as 3 August.

  • Second year Northbound Migration may begin as early as 2 May.

  • Southbound Migration began as early as 3 August and as late as 24 October.

  • One non-breeding female made four complete migrations in a four year period:  twice to Idaho and twice to Oregon.

  • Another female, also over a four year period, acquired a mate in her second calendar year of life and made two complete migrations and became resident upon acquiring a mate.

    Recaptures:

     All (n = 96)

        91 (95%) were philopatric (<10 terr.)

        78 (81%) were strongly philopatric (<5 terr.)

     Females (n = 36)

        33 (92%) were philopatric

        26 (72%) were strongly philopatric

     Males (n = 60)

        58 (93%) were philopatric

        52 (87%) were strongly philopatric

     Encounters:

    (n = 48)

    37 (77%) were philopatric (natal or adjacent 10-min Block)

FURTHER READING - ADDITIONAL PUBLISHED RESEARCH:

Briggs, C. W., Hull, A. C., Hull, J. M., Harley, J. A., Bloom, P. H., Rosenfield, R. N., & Fish, A. M. (2020). Natal dispersal distance and population origins of migrant red-tailed hawks and Cooper's hawks. Journal of Raptor Research, 54(1), 47-56.

McCrary, M. D., Bloom, P. H., Porter, S., & Sernka, K. J. (2019). Facultative migration: New insight from a raptor. Journal of Raptor Research, 53(1), 84-90.

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