Morphometry, Feeding Ecology, Haematology, and Heavy Metal Bioaccumulation in House Crow (Corvus splendens) from Central Punjab, Pakistan

Abstract

The house crow (Corvus splendens) is a highly adaptable urban bird widely distributed across Pakistan and serves as a potential bioindicator of environmental health. This study evaluated morphometry, feeding ecology, haematology, and tissue trace‑metal burdens in house crows from cultivated and semi‑urban landscapes of Okara District (Central Punjab, Pakistan) during March-June 2023. Sixty adults were captured, and a subset of 24 individuals (12 males and 12 females) was processed for detailed laboratory analyses. Standard morphometrics were recorded using a digital balance and digital calipers. Diet was assessed via gut‑content examination and categorized into major food groups. Blood was collected from the brachial vein for routine haematology, and liver, kidney, and pectoral muscle tissues were digested (HNO₃/HClO₄) and analyzed by atomic absorption spectrophotometry for Zn, Cd, Ni, Fe, and Cr. Sexual dimorphism was limited, with males marginally heavier and slightly larger in wingspan. Gut contents indicated an opportunistic omnivorous diet with a high frequency of insects (83.3%), wheat grains (62.5%), and anthropogenic refuse (50%). Mean haematological indices were within expected avian ranges (e.g., RBC 2.93 ± 0.45 ×10⁶/µL; WBC 26.87 ± 1.02 ×10³/µL; PCV 37.97 ± 2.00%). Trace metals were detected in all tissues, with Zn and Fe generally highest in liver and Cr relatively elevated in muscle. These findings provide baseline ecological and physiological information for C. splendens and support its utility as a sentinel species for monitoring anthropogenic food dependence and trace‑metal exposure in agro‑urban Punjab.