Hummingbirds are some of the most fascinating birds in the world. Their ability to hover mid-air and fly backwards sets them apart from other bird species. These tiny birds have captured people’s imaginations for centuries. In recent years, there has been much discussion around whether hummingbird populations are increasing or decreasing. Understanding hummingbird population trends is important for conservation efforts. In this article, we will explore what the data says about hummingbird populations.
Hummingbird Population Data
Quantifying hummingbird populations is challenging. These tiny birds are difficult to systematically track over time. However, data from citizen science initiatives and field surveys provide some insight into general population trends. The North American Breeding Bird Survey is one of the most comprehensive datasets on bird populations over time. Analysis of Breeding Bird Survey data from 1966-2015 suggests that some hummingbird species like the Ruby-throated Hummingbird have experienced population increases in recent decades. However, other species like the Rufous Hummingbird show declining trends. There is significant variation between different regions and species.
Ebird is another citizen science database that tracks bird sightings reported by the public. Ebird data indicates rising hummingbird sightings in recent years for species like the Anna’s Hummingbird and the Ruby-throated Hummingbird. However, absence from Ebird data does not necessarily mean a species is declining. The data is heavily reliant on volunteer participation, so trends may simply reflect changes in observer effort.
Researchers have also conducted field surveys focused specifically on hummingbirds. Surveys across the western United States indicate an increase in hummingbird populations between the 1970s and early 2000s. However, data since the early 2000s is more limited. The diversity of data sources makes it challenging to construct a definitive narrative about overall hummingbird population trajectories.
Why Are Hummingbird Populations Increasing?
Assuming hummingbird populations are stable or increasing in many regions, what factors may be contributing to this trend? Here are some of the main theories:
Backyard Feeding
The rising popularity of backyard bird feeding is likely benefitting hummingbird populations. More people are setting up hummingbird feeders and planting nectar-producing flowers in their gardens. This supplemental food source supports higher hummingbird densities, especially during migration when food is scarce. Banding studies show higher survival rates for hummingbirds supplemented with feeders. Backyard habitats may also provide protection from predators.
Urbanization
Some hummingbird species like the Anna’s Hummingbird have adapted well to urbanization. They thrive in city parks and backyards. Urban heat islands provide warmer climates that allow these hummingbirds to expand their ranges northwards. Urban trees, exotic flowers and backyard feeders provide plentiful food sources. As urban areas expand, they create more habitat for species adapted to city life.
Climate Change
Warmer temperatures associated with climate change may also benefit hummingbirds by improving survival rates and allowing earlier breeding. Some species have expanded their distributions northward as climates warm. However, climate change brings extreme weather that may negatively impact hummingbirds during migration. The overall effect is complex and may vary between species.
Habitat Conservation
Conservation of natural habitats helps protect hummingbird populations. Legal protections for important nesting sites and migration stopover habitats ensure that these birds have the resources they need to thrive. Expansion of protected areas along migration routes may contribute to rising populations for some species.
Pesticide Bans
Banning highly toxic pesticides like DDT has reduced mortality and supported recovering hummingbird populations. Protections put in place by the Environmental Protection Agency in the 1970s allowed species like the Ruby-throated Hummingbird to rebound after experiencing significant declines from pesticide use.
Threats Facing Hummingbirds
While some hummingbirds are thriving, others still face substantial threats to their populations. Here are some of the primary issues putting pressure on hummingbird species:
Habitat Loss
Agriculture, logging, development and other human activities lead to loss and fragmentation of forests and meadows that hummingbirds depend on. For example, clearance of oak woodlands in California has reduced habitat for native Anna’s and Rufous Hummingbirds.
Climate Change
Although warming temperatures benefit some northern hummingbirds, climate change may threaten species adapted to cooler climates like the Berylline Hummingbird. Droughts and wildfires associated with climate change can destroy crucial flowering plants and nesting sites.
Invasive Species
Invasive plant species disrupt native habitats relied on by hummingbirds. Introduced insects and diseases can also damage hummingbird food sources. For example, the hemlock woolly adelgid kills eastern hemlock trees that Rufous Hummingbirds nest in.
Pesticides
Improper use of pesticides reduces insect prey for hummingbirds. Herbicides also kill flowers that provide nectar. Residual accumulation of banned pesticides like DDT may still impact some populations.
Research Needs
Expanding research efforts focused on hummingbirds will help fill key knowledge gaps. Some areas that require further study include:
- Long-term monitoring programs to track population trends for poorly studied species.
- Studies on how hummingbird migration patterns are changing with climate shifts.
- Impacts of urbanization and suburban sprawl on hummingbird populations.
- Effects of pesticides and other environmental contaminants on hummingbirds.
Banding programs and citizen science efforts that engage public participation can supplement academic research. Creative technology applications also have potential to advance hummingbird research through photography, radar studies and online data platforms.
Protecting Hummingbirds into the Future
Supporting thriving hummingbird populations requires protecting essential habitats and minimizing threats. Here are some ways we can help hummingbirds moving forward:
Habitat Conservation
Preserving meadows, scrublands, forests and wetlands through parks, reserves and sustainable land management ensures hummingbirds have the habitat they need.
Backyard Habitats
Providing nectar feeders, native plants and nest boxes around homes and in urban green spaces gives hummingbirds sanctuary in developed areas.
Pesticide Regulation
Following label directions carefully when using pesticides and encouraging responsible policies that protect wildlife can reduce pesticide threats.
Migration Corridors
Maintaining networks of stopover habitats along migration routes helps sustain migrating hummingbird populations.
Climate Action
Implementing policies that promote clean energy and minimize greenhouse gases will help curb severe climate change impacts on hummingbirds.
The Outlook for Hummingbirds
Some hummingbird species appear to be adapting well to human changes to the landscape and climate, as evidenced by population increases documented in citizen science databases. However, long-term monitoring data is still lacking for many species. Targeted conservation practices focused on habitat protection, backyard habitats, pesticide regulation and climate action can support hummingbirds into the future. Sustained public enthusiasm for these charismatic birds will help ensure they continue charming us with their hover-and-sip feeding behaviors for generations to come.
