Table 9. Qualitative comparisons among adult femora.
| Taxon | Cross-sectional shape | ICL and OCL present | Composition of Middle Cortical Layer | Relative vascular density | Primary vascular orientation |
|---|---|---|---|---|---|
| California Quail1 (Callipepla californica) |
circular to ovate | yes; OCL thicker (~1/4-1/3 cortex) but ICL more distinct | woven with simple canals/regional fibrolamellar | moderate | longitudinal |
| Wild Turkey1 (Meleagris gallopavo) |
circular to ovate | yes; ICL thicker and more distinct | fibrolamellar | high | circumferential/plexiform |
| Western Gull2 (Larus occidentalis) |
circular | yes; equal thickness, ICL more distinct | fibrolamellar | high | reticular |
| American Kestrel3 (Falco sparverius) |
circular | yes; equal thickness, ICL more distinct | parallel-fibered with regional fibrolamellar | moderate | longitudinal |
| Red-tailed Hawk3 (Buteo jamaicensis) |
circular | yes; ICL thicker and more distinct | fibrolamellar | high | reticular-longitudinal |
| White-tailed Kite3 (Elanus leucurus) |
circular | yes; equal, ICL more distinct | fibrolamellar bone with regional woven bone w/simple canals | moderate | longitudinal |
| Barn Owl3 (Tyto alba) | circular | yes; equal thickness, ICL more distinct | fibrolamellar | high | reticular-longitudinal |
| Great-horned Owl3 (Bubo virginianus) |
circular | yes; ICL thicker and more distinct | fibrolamellar | high | longitudinal |
| Mourning Dove4 (Zenaida macroura) |
circular | yes; OCL thicker (comprises almost entirety of cortex) | small patches of weakly woven with sparse simple canals | low | longitudinal |
| Anna’s Hummingbird5 (Calypte anna) |
circular | yes; ICL incipient(?), OCL dominates cortex | none | avascular | — |
| Green-cheeked conure5 (Pyrrhura molinae) |
circular | yes; OCL thicker, about 1/3 of cortex | woven bone with simple vascular canals; patches of fibrolamellar bone | low | longitudinal |
| House Finch5 (Haemorhous mexicanus) |
circular | ICL absent; OCL ~1/2 of cortex | parallel-fibered with regional woven bone | low | longitudinal |
Note:
Vascular density in adults was ubiquitously lower than in younger growth stages, thus relative density among adults only is reported here. “Middle cortical layer” refers to the portion of the cortex located between the OCL and the ICL. Descriptions of the ICL as “more distinct” refer to the very high level of organization of tissue in this layer, which appears strongly lamellated and has a high birefringence. Developmental mode is indicated by color number superscript: orange1, precocial; yellow2, semi-precocial; green3, semi-altricial 1; blue4, semi-altricial 2; purple5, altricial.