Nesting success rates in western wildland areas may be lower such as in Utah, where 53.5% of nests fledged young, with many of the failures attributable to owl predation. Data from Oregon showed that 74% hatched and 61.4-69% successfully fledged, a much lower rate of nest success than goshawks, at 90.4%, and, surprisingly, than sharp-shinned hawks, at 91.7%. However, in the Oregon data, the number of eggs hatched was higher in Cooper's at 74% than in sharp-shinned hawks, at 69.4% (but not than the goshawk’s). In North Dakota, better habitat such as upland forest showed much higher breeding success levels (at least 1 fledgling in 86% of 26 nests) than in poorer habitats such as narrow riparian strips, in which 1 fledgling was produced in 57% of 44 nests. Younger forest in North Dakota was surprisingly preferred, with the average estimated age of trees used by Cooper's at 59.9 against a random tree age in the area of 74.6. It was found that adult female who mated with males who provisioned food at a higher rate produced 1.6 more fledglings on average. Yearling females in northeastern Oregon tended to use younger successional stands than older females and tended to have lower productivity in clutch size and brood counts. Among 70 studied male hawks in Wisconsin, the number of fledged young produced in their lifetime was similar in males who didn’t breed until they were two years old (mean of 8.8 fledglings) compared to those who started breeding as yearlings (mean of 8.7 fledglings), with the most successful studied male having started breeding in his second year and had produced 32 fledglings by the time he was nine years of age. In Arizona and New Mexico, 23% of nests failed altogether and 56.5% of 23 nests in Wisconsin failed during incubation. A high genetic diversity, or allele level, was found in the nestlings of the urbanized population of Tucson, ensuring a hardy local population despite historic concerns about the parasite levels of nestlings in these populations. The Cooper's hawks can be a long-living bird. Some authors credit lifespans of up to 8 years of age in the wild. The oldest recorded bird recorded among migrants that bred in Oregon was 10 years and 5 months old. The oldest recorded breeding bird was a 12 year old female in British Columbia while the oldest recorded wild bird was a 20 year old, 5 month old banded in migration.