At Archbold Biological Station, decades of field observations are helping scientists better understand one of nature’s oldest relationship strategies: long-term monogamy.
A new study in Animal Behaviour found that Florida Scrub-Jays that remain with the same partner for longer periods produce more offspring, while pairing with significantly older mates may reduce survival for the younger bird in the pair.
The study, titled “Breeding experience and pair-bond duration influence reproductive success but have less impact on survival in an avian cooperative breeder,” (DOI: 10.1016/j.anbehav.2026.123646) draws on 35 years of data from Archbold’s internationally recognized Florida Scrub-Jay research program.
Florida Scrub-Jays are one of the few bird species known for forming long-term monogamous pair bonds. Some pairs remain together for more than a decade, and unlike many bird species, extra-pair offspring are very rare.
One challenge in studying long-term monogamy is separating the effects of age, breeding experience, and pair-bond duration, all of which can influence reproductive success. Because Archbold researchers have followed individual Florida Scrub-Jays throughout their lives for decades, the dataset includes birds of different ages, breeding histories, and pair-bond durations. Some birds began breeding later in life, some entered new pair bonds after years of breeding experience, and others remained with the same mate for many years. This variation allowed researchers to disentangle factors that are often difficult to separate in studies of long-term monogamy.
The researchers found that both breeding experience and longer pair-bond duration independently improved reproductive success, even after accounting for factors such as territory size, population density, food availability, and group composition. Pairs breeding for the third time produced 44% more young than pairs breeding together for the first time. Likewise, pairs in which both birds had at least one year of breeding experience produced 50% more young than pairs composed of first-time breeders.
In other words, experienced birds produced more offspring, but birds that remained with the same partner for longer periods also had greater reproductive success.
The study also uncovered an unexpected pattern: younger birds paired with substantially older mates had lower odds of surviving the non-breeding season.
This finding may help explain why mate switching and divorce remains relatively uncommon in Florida Scrub-Jays despite opportunities to form new pair bonds. While changing partners may sometimes be possible, doing so could carry costs if a bird pairs with an inexperienced or substantially older mate.
The work highlights the scientific value of Archbold’s long-term Florida Scrub-Jay dataset, one of the longest continuous studies of an individually marked bird population in the world. Researchers have tracked generations of birds across the Lake Wales Ridge, allowing scientists to study behavioral and ecological questions that would be difficult or impossible to answer through shorter-term projects.
Most previous studies of pair-bonding and monogamy have focused on laboratory animals or primates. This research provides rare evidence from a wild bird population that long-term pair bonds can independently contribute to reproductive success, helping scientists better understand how monogamy evolves and persists in long-lived species.
The study was authored by Guy Beauchamp, Tori D. Bakley, John W. Fitzpatrick, and Sahas Barve. Funding supporting the long-term dataset included grants from the National Science Foundation, along with support from Archbold Biological Station, the Cornell Lab of Ornithology, and the Field Museum of Natural History.
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Archbold is a world-class laboratory located on over 20,000 acres in the Headwaters of the Everglades. Archbold’s mission is to build and share the scientific knowledge needed to protect the life, lands, and waters of the heart of Florida and beyond. With seven ecological research programs, Archbold science is deeply trusted and critical for conservation of species and natural systems in Florida. Archbold is a 501 (c)(3) non-profit organization founded in 1941, dedicated to science, conservation, and education.
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Animal Behaviour
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Breeding experience and pair bond duration both increase reproductive success in an avian cooperative breeder
13-Jul-2026