Nuthatches are small songbirds found throughout North America, Europe, and Asia. They get their name from their habit of wedging nuts and seeds into tree bark and then hacking away at them with their long bills to get at the kernel inside.
Nuthatches are cavity nesters, often reusing old woodpecker holes or natural hollows in trees. They line their nests with soft materials like fur, feathers, grass, and bark. Nuthatches form monogamous breeding pairs and cooperate to build their nests together. But do nuthatches actually mate for life?
Nuthatch Courtship and Pair Bonding
Nuthatches form breeding pairs through elaborate courtship rituals in early spring. The male will sing melodious songs and perform elaborate dances to attract a female. Once paired, the male will continue to sing to the female and feed her morsels of food to cement the bond.
Nuthatches are very territorial and will defend their breeding and foraging areas against intruders. Both the male and female work together to chase away any competing birds. This cooperative defense helps strengthen the pair bond.
Research shows that the same male and female nuthatch will often return to the same breeding territory year after year. One study found that a banded pair of white-breasted nuthatches returned to the same nesting cavity for four years in a row. This suggests that nuthatch pairs can remain monogamous for multiple breeding seasons.
Do Nuthatches Divorce?
While nuthatches show high mate and site fidelity, they do occasionally “divorce” and find new mates. One study in England found that 18% of marked Eurasian nuthatch pairs dissolved after a breeding season and at least one member paired up with a new mate the next year.
There are a few reasons why nuthatches may swap mates:
– Death of one member of the pair
– Failure to successfully breed
– Competition for high quality nesting sites
Younger or less experienced birds are more likely to divorce and find new mates than older, established pairs. But divorce rates in nuthatches are still relatively low compared to other bird species.
Nuthatch Nesting and Parenting
Nuthatches that do maintain pair bonds work closely together to raise their young. The female lays 5-9 eggs which she incubates for about two weeks while the male brings her food.
Once the chicks hatch, both parents work tirelessly to feed the demanding babies. They may deliver over 400 meals per day! The chicks fledge about three weeks after hatching but continue to be fed by the parents for several more weeks as they learn to forage on their own.
This high level of cooperation in breeding, nesting, and parenting behaviors helps strengthen the pair bond in nuthatches.
Do Nuthatches Remate After Losing a Partner?
When a mated nuthatch dies, the remaining bird will try to find a new mate. However, studies show that the surviving nuthatch will often return to the same breeding territory rather than try to claim a new area with a new mate.
One study of color-banded red-breasted nuthatches found that a surviving female returned to her previous breeding territory even after the death of her male. She then paired up with a new male who joined her in that territory.
This shows that while nuthatches do try to find new mates after losing a partner, they also demonstrate strong fidelity to their prior nesting sites. Their next mate often has to fit into their established home range.
Signs That Nuthatches Mate For Life
While divorce and remating does occur, most evidence suggests that nuthatches tend to mate for life and demonstrate monogamous behaviors:
– Strong pair bonding behaviors through courtship rituals
– Cooperative defense of territory against intruders
– High mate fidelity across breeding seasons
– Cooperative breeding and parenting effort
– Returning to the same nest site and territory year after year
– Low rates of divorce compared to other species
– Willingness of new mates to join established territories
So while nuthatch bonds may occasionally break, they appear predisposed to monogamy and long-term pair bonding. Their life history strategy favors maintaining pair bonds across years.
Other Bird Species That Mate for Life
Nuthatches are not the only birds that form lasting pair bonds. Other birds that tend to mate for life include:
Albatrosses
– Form intense pair bonds that last for many years.
– Use elaborate mating dances and vocalizations.
– Share parenting duties equally.
– Will find a new mate after one dies, but usually in subsequent breeding seasons.
Bald Eagles
– Mate for life with low divorce rates.
– Return to massive nests built together over many years.
– Work cooperatively to defend territories and raise eaglets.
Turkeys
– Mate fidelity can last over 15 years.
– Male turkeys court females with elaborate strutting rituals.
– Work together to build nests, incubate eggs, and raise poults.
Swans
– Usually retain the same mates year after year.
– Male helps build the nest and both parents warm the eggs.
– Well known for their bonded pairs swimming together.
Prairie Voles
– A rodent species, not a bird, but they form monogamous bonds.
– Extended male-female contact enables pair bonding hormones.
– Both parents help raise pups.
Benefits of Monogamy and Mate Bonding in Birds
Why do birds like nuthatches form bonded pairs instead of seeking new mates each year? Long-term monogamy may offer several evolutionary benefits:
– **Increased reproductive success** – Mate familiarity may improve breeding coordination and number of offspring.
– **Better parental care** – Both parents investing gives chicks a survival advantage.
– **Shared defense duties** – Cooperatively defending resources provides benefits.
– **Disease resistance** – Longer-term contact enables immunity against each other’s diseases.
– **Reduced stress** – Established pairs experience decreased corticosterone stress hormone.
So while birds aren’t legally married to their mates, ecological data suggests they gain real benefits from maintaining long-term pair bonds and monogamous behaviors.
Conclusion
While nuthatch divorce and remating does occur, most evidence indicates that they have a natural tendency towards monogamy and long-term pair bonding. Their courtship rituals, coordinated breeding behaviors, biparental care, and mate fidelity across years suggest that nuthatches do psychologically “mate for life” even if they don’t always stay with just one partner. Their evolutionary history seems to have selected for bonding strategies that favor keeping the same mate over seasons, though circumstances can lead to new pairings. So while they may not mate for literal life, nuthatches certainly form lasting pair bonds that increase reproductive success and likely bring mutual benefits for the mating pair.