Mallard x Mottled Duck (Anas platyrhynchus x fulvigula)
NOTE: recent research calls into question that green on the head and other "Mallard" phenotypic features are indicative of hybridization, suggests that they are the result of incomplete lineage-sorting coupled with hormone-related expression of otherwise suppressed traits in young birds. See:
Genomic and morphological data shed light on the complexities of shared ancestry between closely related duck species | Scientific Reports (nature.com)
this research also suggests that the bulk of verified hybridization is the result of wild Mexican or Mottled Ducks crossing with domestic rather than wild Mallards.
TEXAS: El Paso Co; Sunset Canal S of Sunset St - February 2023
Mexican Duck x Mallard
hens in all photos likely pure or indistinguishable from pure MEDU
drake with curled central tail retrices likely 75% or greater MEDU
drake with green in head likely F1 50/50 hybrid between MALL x MEDU
ARIZONA: Cochise Co; Willcox - Lake Cochise & Twin Lakes Golf Course - December 2022
odd combination of MALL and MEDU traits
TEXAS: Kinney Co; Fort Clark Springs - December 2021
likely F1 50/50 hybrid between MALL x MEDU
TEXAS: Reeves Co; Sandia Wetlands - January 2021
this flock contained a wide assortment of crosses and backcrosses between MALL & MEDU ranging from pure MEDU, 75% or more MEDU, 50/50 crosses, and at least one 75% MALL
FLORIDA: Sumpter Co; Lake Okahumpka Park - March 2019
50/50 MALL X MODU + likely pure MODU