It's not such a fine romance

Ducks pair for a season but geese will mate for life — and it’s purely convenience, says Mike Swan

Have you noticed how often ducks coming to a flight pond arrive in twos, especially later in the season? It’s no accident — by this time of year the breeding pairs have mostly formed. If you are a sentimental old fool like me, you could worry that you are likely to leave a bird without a mate, but it does not work like this.

What actually happens, with pretty much every species of duck, is that they form a pair bond each year for breeding which breaks down afterwards. Since most members of most species also migrate, often to the Arctic or near-Arctic breeding grounds, they have a short summer in which to find a nest site, lay a dozen or so eggs, incubate, then rear a brood.

In the case of a mallard, for example, it would need two weeks to complete a clutch, four to incubate, and eight for the young to fledge.

Add a couple of weeks to get reasonably strong on the wing ready for migration, and you end up with a four-month breeding season, so turning up already paired and raring to go is a distinct advantage.

Absent fathers

Once the clutch is laid, the father loses interest and leaves the mother to do the work, while he hangs out with the lads until moulting and migration time. And he will happily shatter all your dreams about being part of an ever-faithful pair by forcing himself on any unattached female duck that happens into view.

In areas where the birds congregate in higher numbers — such as town parks where the free food from people keeps them concentrated — this can result in extremely poor productivity. The ducks that leave the nest for a quick feed get harassed so much that the eggs can chill.