Spring bird migration as a dispersal mechanism for the hemlock woolly adelgid

Dispersal patterns of Reeves's pheasant based on genetic and behavioral evidence

Dispersal is an important life history trait that plays a crucial role in avoiding inbreeding. Uncovering the dispersal pattern of a threatened species facilitates conservation efforts. Most species of Galliformes are forest-dwelling terrestrial birds with a weak dispersal ability and high conservation priorities. However, little is known about the dispersal behavior and dispersal pattern of Galliformes species such as Reeves's pheasant Syrmaticus reevesii, a globally vulnerable species endemic to China. Here, we integrated behavioral and genetic analyses to investigate the dispersal pattern of Reeves's pheasant. Our results revealed that both females and males would disperse, although the overall dispersal pattern was more likely to be male-biased. Reeves's pheasant population had a low level of genetic diversity and a mild level of inbreeding. Speculation low genetic diversity was resulted from fragmented habitat, and male-biased dispersal may reduce the opportunity of inbreeding. Our research indicated that sex-biased dispersal patterns may be a behavioral mechanism adopted by wildlife to avoid inbreeding in a fragmented habitat.

Geomagnetic disturbance associated with increased vagrancy in migratory landbirds

Rare birds known as "accidentals" or "vagrants" have long captivated birdwatchers and puzzled biologists, but the drivers of these rare occurrences remain elusive. Errors in orientation or navigation are considered one potential driver: migratory birds use the Earth's magnetic field-sensed using specialized magnetoreceptor structures-to traverse long distances over often unfamiliar terrain. Disruption to these magnetoreceptors or to the magnetic field itself could potentially cause errors leading to vagrancy. Using data from 2 million captures of 152 landbird species in North America over 60 years, we demonstrate a strong association between disruption to the Earth's magnetic field and avian vagrancy during fall migration. Furthermore, we find that increased solar activity-a disruptor of the avian magnetoreceptor-generally counteracts this effect, potentially mitigating misorientation by disabling the ability for birds to use the magnetic field to orient. Our results link a hypothesized cause of misorientation to the phenomenon of avian vagrancy, further demonstrating the importance of magnetoreception among the orientation mechanisms of migratory birds. Geomagnetic disturbance may have important downstream ecological consequences, as vagrants may experience increased mortality rates or facilitate range expansions of avian populations and the organisms they disperse.