Prairie Falcon Falco mexicanus Schlegel       Field Guide IDs: NG-124; G-80; PE-162; PW-pl 17; AW-pl 320; AM(l)-264 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy F -M I: 29-33 DAYS SEMIALTRICIAL 2 30 feet - 40 feet (20 feet - 400 feet) CREVICE 4-5 (2-7) MONOG F: 35-42 DAYS MF SMALL ..... .....MAMMALS INSECTS LIZARDS LOW .....PATROL BREEDING: Open habitat in mountainous regions, shortgrass prairie, alpine tundra. 1 brood. DISPLAYS: Male performs aerial gymnastics, cutting parabolas and calling in front of perched female; she calls, occ joins flight. Male also struts on nesting ledge. NEST: On cliff ledge, occ in rock crevice, always facing open habitat. Usu unlined. Rarely use earthen bank. EGGS: White/pinkish-white, marked with browns. 2.1" (52 mm). DIET: Can overtake most birds directly, flushing ground dwellers by flying low, but also hovers and stoops for other prey. CONSERVATION: Winters s to Baja, n Mexico. Some eggshell thinning and mercury poisoning reported (accumulated esp from taking seed-eating Horned Lark). Declining in UT, w Canada, and agricultural CA. NOTES: Weak nest site tenacity. Clutches smaller in e portion of range. In nest defense, male circles above, female leaves nest only as last resort. Parental care of young continues after fledging. Female ca. 33% larger than male. With lighter wing loading, outflies Peregrine at high altitude. STANFORD. NOTES: Similar Species: Peregrine Falcon ESSAYS: Raptor Hunting; Size and Sex in Raptors; Conservation of Raptors; Wing Shapes; Metallic Poisons; Site Tenacity. REFERENCES: Allen et al., 1986; Cade, 1982; Enderson, 1964; Marti and Braun, 1975.