Bird Migration Patterns in the Himalayas Linked to Diet and Habitat Availability

October 4, 2023

A recent study, published in the journal Global Ecology and Biogeography, has examined the seasonal elevational shifts of 302 Himalayan bird species, revealing that the majority of these birds migrate downslope during the winter. However, a small proportion of species found in low elevations migrate upslope. The study also explores the influence of diet and thermal regimes on these elevational shifts.

Factors Driving Seasonal Elevational Shifts

The study suggests that diet and habitat availability play a significant role in driving seasonal elevational shifts in Himalayan birds. Birds that display the most significant elevational shifts tend to remain within narrow thermal regimes. These findings highlight the complex interplay of ecological factors influencing bird behavior.

Research Methodology

The researchers analyzed data from the eBird community science dataset, covering the years 2011 to 2022, to study elevational shifts in 302 Himalayan bird species. They also considered factors such as diet, dispersal capability, and thermal regime, which refers to the temporal and spatial distribution of temperature.

Key Findings:

Approximately 65% of Himalayan bird species in the eastern and western Himalayas displayed seasonal elevational shifts within their range.
Climate change is suggested as a potential factor influencing these shifts, particularly for species breeding at high altitudes.
Species that breed at high altitudes do not spend the winter there, but there were no observations of short or small upslope shifts for these birds.
Temperate mountains, with cold winters and warm summers, experience significant shifts in seasonality.

Ecological Risk and Thermal Regime

The ecological risk index showed the highest risk in the Hirakud wetland, followed by Talcher, Bhadrak, Titlagarh, Chilika, Chandaneswar, Koraput, and Daringbadi.
Birds in the east and west Himalayas displayed a significant negative association with thermal regimes, indicating the impact of temperature on their elevational limits.
The availability of food was a decisive factor in determining elevational shifts, with different dietary preferences influencing the distances shifted.

Future Implications

Climate change and changes in land use may affect the elevational migration of birds in the future, with potential consequences for population dynamics.
Limitations exist in how far birds can shift their ranges based on factors like food availability and habitat constraints.
Resident birds may also need to shift their ranges to higher altitudes, but their ability to adapt may be limited.

« Previous Post Next Post »