Tracking Migratory Patterns of Rough-legged Buzzards Reveals a Novel "Foxtrot Migration" Behavior and Dynamic Non-breeding Ranges

Core Concepts

Rough-legged buzzards exhibit a novel "foxtrot migration" pattern characterized by alternating quick and slow phases of movement during the non-breeding season, driven by environmental factors like snow cover dynamics. This results in a "dynamic non-breeding range" that changes throughout the season.

Abstract

The study investigated the migratory behavior of Rough-legged Buzzards using GPS tracking data. It revealed a previously unknown pattern of migration, termed "foxtrot migration", which is characterized by alternating quick and slow phases of movement during the non-breeding season.
During the quick phases, the birds rapidly traverse unfavorable habitats like the taiga zone. In contrast, the slow phases involve directional and continuous movements through more favorable grassland and cropland areas, driven by changes in snow cover dynamics. This results in a "dynamic non-breeding range" that shifts geographically throughout the season, rather than a static wintering ground.
The authors argue that this foxtrot migration pattern and dynamic range have important implications for accurately mapping species distributions and assessing conservation status. Traditional methods like mid-winter surveys may fail to capture the full extent of a species' non-breeding range. Similarly, declines observed in one part of the range may reflect changes in range dynamics rather than overall population decline.
The study highlights the value of advanced tracking technologies in revealing complex migratory behaviors, which is crucial for understanding the impacts of environmental change on migratory species. Incorporating these new insights into conservation strategies is essential for effective protection of bird populations in the Anthropocene.

Stats

"Rough-legged buzzards started their fall migration (quick phase) on 28 September (271±11 days) and ended on 12 October (285±11 days)."
"The mean latitude/longitude where the birds ended their fall migration was 55.57±1.92°/49.35±5.63°."
"During the winter, birds continued to migrate at a slower pace down to 49.53±2.01° latitude (on 5 February, 36±40 days) and 34.29±5.11° longitude (on 24 January, 24±47 days)."
"Afterward, during the second part of the slow phase, the birds returned to 55.52±2.63° latitude and 49.79±8.24° longitude to start the spring migration."
"The quick phase was 1415±50 km long, whereas the slow phase (one part) was 1026±55 km, i.e., 389±60 km shorter."
"During quick phase, birds flew for 15±3 days, and one part of slow phase lasted 100±4 days, i.e., 85±5 days longer."
"The migration speed was 104±6 km/day during the quick phase and 12±7 km/day during the slow phase, i.e., about eight times higher."

Quotes

"During quick phases, Rough-legged buzzards cross the forest zone, while during slow phase, they migrate within the grassland and cropland zone."
"If birds fly immediately to the southwest and stay there for the whole winter, they would experience snow cover conditions ranging from 1.4±0.2 % in October to 81.1±5.0 % in January."
"If birds stay where they ended the fall migration, they will find themselves in situations with more snow cover (85.2% vs. 99.5%), but more means that snow cover will be close to 100% for several months in this hypothetical situation."

Key Insights Distilled From

Quick-quick-slow: the foxtrot migration and dynamic non-breeding range

by Pokrovsky,I.... at www.biorxiv.org 03-15-2023

https://www.biorxiv.org/content/10.1101/2023.03.13.532370v2

Deeper Inquiries

How might the foxtrot migration pattern and dynamic non-breeding ranges of other migratory bird species, particularly those in different geographic regions, compare to the Rough-legged Buzzard?

The foxtrot migration pattern observed in the Rough-legged Buzzard, characterized by alternating quick and slow phases during the non-breeding period, may have variations in other migratory bird species in different geographic regions. For species in regions with different environmental factors influencing their movements, the specifics of the foxtrot migration pattern may vary.
In species that migrate between breeding grounds in the Arctic and non-breeding grounds in mid-latitudes, similar to the Rough-legged Buzzard, the foxtrot migration pattern may involve directional and continuous movements influenced by factors like snow cover dynamics. However, the timing, duration, extent, and speed of the quick and slow phases may differ based on the specific environmental conditions and resource availability in their respective habitats.
For migratory bird species in regions with different seasonal patterns or food availability drivers, the foxtrot migration pattern may manifest in unique ways. Some species may exhibit similar alternating fast and slow movements during the non-breeding period, while others may show variations based on the specific ecological factors influencing their movements.
Overall, while the core concept of foxtrot migration involving alternating quick and slow phases may be applicable to various migratory bird species, the specific details and dynamics of this pattern are likely to vary based on the species' geographic location, ecological requirements, and environmental influences.

What are the potential implications of climate change-driven shifts in snow cover dynamics on the foxtrot migration patterns and conservation status of Arctic-breeding species like the Rough-legged Buzzard?

Climate change-driven shifts in snow cover dynamics can have significant implications for the foxtrot migration patterns and conservation status of Arctic-breeding species like the Rough-legged Buzzard. As snow cover dynamics play a crucial role in determining the availability of prey for species like the Rough-legged Buzzard, changes in snow cover patterns can directly impact their migratory behavior and habitat selection during the non-breeding period.
With climate change leading to alterations in snow cover duration, extent, and timing, Arctic-breeding species may experience shifts in their non-breeding ranges and migration patterns. For species exhibiting foxtrot migration, changes in snow cover dynamics can influence the timing and duration of the quick and slow phases of migration, as well as the selection of suitable habitats for foraging and resting.
These shifts in snow cover dynamics can also affect the conservation status of Arctic-breeding species. If changes in snow cover lead to reduced prey availability in certain areas, species like the Rough-legged Buzzard may need to adjust their migration routes and non-breeding ranges to find suitable food sources. Failure to adapt to these changing environmental conditions could result in population declines and habitat loss for these species.
Therefore, understanding the impact of climate change on snow cover dynamics and its implications for migratory behavior is crucial for developing effective conservation strategies to protect Arctic-breeding species and their habitats in the face of ongoing global environmental challenges.

How can the insights gained from studying the foxtrot migration behavior be applied to improve the design and implementation of conservation strategies for migratory bird populations in the face of global environmental challenges?

The insights gained from studying foxtrot migration behavior in migratory bird populations can be instrumental in enhancing the design and implementation of conservation strategies to address global environmental challenges. Here are some ways these insights can be applied:

Dynamic Range Mapping: Incorporate the concept of dynamic non-breeding ranges into conservation planning by accurately mapping the temporal heterogeneity of bird populations throughout the year. This can help identify critical habitats and migration corridors that are essential for species survival.

Climate Change Adaptation: Use knowledge of foxtrot migration patterns to anticipate how climate change-driven shifts in environmental factors, such as snow cover dynamics, may impact migratory behavior and habitat use. Conservation strategies can then be tailored to address these changing conditions and ensure the long-term viability of bird populations.

Targeted Conservation Efforts: Focus conservation efforts on key areas along migratory routes where birds exhibit slow phases of migration, as these habitats are likely crucial for foraging and resting during the non-breeding period. By protecting these areas, conservationists can support the survival of migratory bird populations.

Collaborative Conservation Initiatives: Engage in collaborative efforts with stakeholders across different regions to address conservation challenges faced by migratory bird species. By sharing knowledge and resources, conservationists can work together to implement effective conservation measures that benefit bird populations throughout their annual cycle.

Education and Awareness: Raise awareness about the importance of migratory bird conservation and the unique behaviors, such as foxtrot migration, that these species exhibit. By educating the public and policymakers, conservation efforts can gain support and momentum to address global environmental challenges impacting migratory bird populations.

By applying the insights from studying foxtrot migration behavior, conservationists can develop targeted and adaptive strategies to protect migratory bird populations and their habitats in the face of ongoing environmental changes.