Red-knobbed coot, Fulica cristata, was formerly distributed across several countries in the south-west Palaearctic. Remnant populations are now located in Morocco and Spain. In the latter, the red-knobbed coot is considered critically endangered, and its decline is attributed to changes in agricultural practices in the basins of wetlands, which have affected the quality and quantity of food. However, red-knobbed coot is currently more abundant in Morocco. Foraging behaviour reveals information about an animal’s perception of the place that it currently occupies. Thus, we hypothesised that if habitat quality is lower in Spain than in Morocco, this should be expressed in the foraging activity of coots, which should be greater in Spain to compensate for the lower food availability. Our results supported this prediction: red-knobbed coots spent more time foraging in Spain than in Morocco. Furthermore, we compared the foraging behaviour of red-knobbed and common coots, Fulica atra, in southern Spain, where common coot does not face conservation problems, and found that red-knobbed coots spent more time foraging than common coots to meet daily energetic needs. Overall, our results suggested that constraints of food quality and quantity on habitat use were more severe for red-knobbed coots than for common coots, and that this may be a key factor for the conservation of red-knobbed coot in Spain. Managers should try to facilitate longer hydroperiods in wetlands, which would ensure higher quality food during longer periods for coots.