British Waterfowl Association

Red-breasted Merganser

Red-breasted Merganser drake swimming
Red-breasted Merganser drake — BWA

Red-breasted Mergansers are reasonably scarce in collections. They persistently pick up hard material like sticks and can choke, so enclosures must be scrupulously tidy.

 

Female and eclipse male Red-breasted Mergansers
Red-breasted Merganser pair, male behind in eclipse — Morag Jones
Red-breasted Merganser drake
Red-breasted Merganser drake in breeding plumage — Barry Nicolle

Mergus serrator

Like its larger cousin the Common Merganser, the Red-breasted Merganser is a widespread bird throughout the northern hemisphere, and the range of the two species overlaps widely. Unlike the Common Merganser, which prefers fresh water, the Red-breasted Merganser likes salt water, and is typically found in shallow tidal waters where it dives for fish. Many birds stay on the coast to breed, while others come inland to freshwater lakes and rivers.

Red-breasted Mergansers swimming
Red-breasted Mergansers — Barry Nicolle

Though a relatively silent species, the drakes have a flamboyant display. Courtship and pair formation start in mid-winter and becomes intense as spring migration starts. The flight is fast and direct. Both sexes have spikey crests; in eclipse the drake resembles the duck, but retains the distinctive white wing coverts.

Red-breasted Merganser swimming
Red-breasted Merganser about to dive — Morag Jones

To identify the wild sawbills found in the UK, there is a useful article on Birdguides.

Red-breasted Mergansers require clean water and a high-protein fish-based diet. Nest boxes will encourage them to breed. They like to lay their clutch of 9–10 buff eggs close to water. Incubation is for 29 to 35 days.