Polyandry

This is a Dunnock... a very common bird by all accounts but not as dull as you might think .......

This species makes up for its drab appearance with its breeding behaviour. Females are often polyandrous, breeding with two males at once, and thus giving rise to sperm competition. Males compete for mating access to the female, but DNA fingerprinting has shown that chicks within broods often have different fathers, depending on their success at monopolising access to the fertile female. Males try to ensure their paternity during courtship by pecking at the cloaca of the female to stimulate her to eject the sperm of other males with whom the female has recently mated. Dunnocks take just one-tenth of a second to copulate, and have sex more than 100 times a day. Males provide parental care in proportion to their mating success, so it is not uncommon to see two males and a female provisioning nestlings at one nest. Polyandry is rare in birds, with only about 2% of species showing such a mating system; the majority are monogamous, where one male and one female breed together.

... well who'd have thought it? It's the quiet ones you have to watch!

Apologies for quality of this ... wrong ISO ... only just fledged to manual settings and have a lot to learn ....