Why is the hummingbird population down this year?

The hummingbird population has noticeably declined this year, leaving many bird enthusiasts wondering why. Hummingbirds are a beloved backyard visitor, prized for their bright colors, acrobatic flight, and role as pollinators. A drop in their numbers is cause for concern. In this article, we’ll explore the potential reasons behind the hummingbird decline and what can be done to support these tiny birds.

Weather and Climate Factors

Shifts in weather and climate patterns are likely contributors to the hummingbird population dip. Hummingbirds are highly sensitive to changes in temperature, rainfall, food availability, and storm systems. Here are some weather-related factors that may have reduced hummingbird numbers this year:

• Unseasonable cold periods in their wintering grounds or migration routes. Cold snaps increase metabolic demands on hummingbirds and can be fatal if food sources are scarce.
• A warm, dry spring in breeding areas. Lack of rainfall may have reduced nectar supplies from wildflowers and flowering trees when hummingbirds arrived to nest.
• A hot summer. High temperatures cause more rapid evaporation of nectar sources. Heat waves could have led to dehydration.
• Severe storms. Hummingbirds are lightweight and get tossed around easily by high winds and rain. Storms may have blown migrants off course or killed nestlings.
• Climate change effects. Shifting seasonal patterns, warming temperatures, habitat loss, and increased storms linked to climate change may stress hummingbird populations over the long term.

Hummingbirds have a high metabolism and need to eat frequently to power their beating wings. Any disruption in food availability or temperature regulation can quickly take a toll. Even subtle environmental changes that throw off seasonal timing and resources can impact hummingbird breeding, migration, and survival. Monitoring weather patterns and potential climate influences will be important for understanding hummingbird population trends.

Habitat Loss and Degradation

Loss of natural habitats that hummingbirds rely on is another contributor to declining populations. Hummingbirds are found in a diverse range of habitats during their breeding season, migration, and wintering grounds, including:

• Flowering meadows and prairies
• Scrublands and thickets
• Woodland areas and forest openings
• Riparian corridors along streams and rivers
• Gardens, parks, and backyard landscapes

Hummingbirds depend on native flowering plants in these habitats for nectar and small insects for protein. When natural areas are cleared or fragmented by human development, there are fewer food resources available. Some key habitat threats include:

• Urban sprawl and expanding residential areas
• Agricultural land conversion
• Logging and mining activity
• Brush clearing
• Grassland conversion to farmland
• Draining or pollution of wetlands

Preserving a variety of natural habitats across geographic regions is key to maintaining hummingbird populations. This may involve protecting wilderness areas, improving land management practices, and enhancing habitat corridors between fragmented areas.

Decline of Flowering Plants

One of the most direct impacts of habitat loss for hummingbirds is fewer flowering plants. Development often entails replacing diverse native plant communities with turf grass lawns or non-native ornamental species. This drastically reduces an area’s carrying capacity for hummingbirds. Even parks and nature reserves may lack essential flowers if they are not actively managed to maintain or restore native plant diversity.

Providing continuous access to nectar sources throughout the seasons is critical. Hummingbirds that breed in an area depend on flowers from spring through summer for their nesting cycle. Migrants rely on nectar supplies along their entire route to fuel their travel. A shortage at any point can be detrimental. Ensuring both residential and wilderness areas have ample flowers through landscaping choices and habitat management is key.

Pesticides and Pollution

Environmental contaminants introduce another threat to hummingbird health and food sources. Pesticides applied to agricultural lands or neighborhoods can be absorbed by native plants. The nectar and pollen can then become toxic to hummingbirds feeding on them.

Common pesticides that are harmful to hummingbirds include:

• Neonicotinoids
• Glyphosate
• Organophosphates
• Carbamates

Studies have also found hummingbirds exposed to heavy metals like mercury and lead accumulation in their liver and kidneys. Other pollution concerns are:

• Air pollution accumulating on plants and in soil
• Water pollution affecting flowering trees, shrubs, and wetland vegetation

Minimizing the use of pesticides and reducing environmental pollutants are important steps for protecting hummingbird health.

Disease

Hummingbirds are susceptible to a range of infectious diseases that can be exacerbate by environmental stressors and climate change. Some diseases that may be impacting hummingbird populations currently include:

Aspergillosis

Aspergillosis is a fungal respiratory infection. Changes in temperature and moisture that allow fungal growth may increase outbreaks. The infection can severely weaken or kill hummingbirds.

Avian Malaria

Avian malaria is caused by a parasite transmitted by mosquitoes. Warmer weather may expand the range of the mosquitoes and increase transmission of malaria to new hummingbird populations.

West Nile Virus

West Nile virus originated in Africa but has spread across North America by mosquitoes. While not all infected birds develop symptoms, it can be fatal in some cases.

Avian Pox

Avian pox is a viral infection that causes wart-like growths on birds. It is spread by mosquitoes and between closely packed birds at feeders. Mild infections may resolve, but it can impede flight and feeding.

Supporting hummingbird health by providing clean feeders, controlling mosquito breeding grounds, and prompt treatment of sick birds can help limit the spread of diseases.

Insufficient Food Sources

In addition to less natural food sources, fewer homeowners providing supplemental feeding may be reducing carrying capacity for hummingbirds. Some factors that may be decreasing backyard feeding are:

• Drought conditions limiting nectar plant growth in gardens
• Less consumer education on hummingbird care and feeding
• Economic factors limiting discretionary spending on feeders, nectar, etc.
• Misconceptions that feeding is bad for hummingbird health or migration

Ensuring year-round access to clean nectar feeders, especially during migration periods, is an important way to support hummingbird populations even in lean times. Outreach to provide tips on ideal feeder practices may help fill gaps.

Predators and Competition

Higher populations of predators and competitors may also be playing a role in declining hummingbird numbers in some regions. Some key animal threats include:

• Domestic cats – A severe predator, killing millions of wild birds annually
• Hawks, falcons, and other birds of prey
• Snakes – Especially hummingbird specialist species like the rufous-necked hummingbird snake
• Jays and scrub jays – Raid hummingbird nests for eggs and chicks
• Squirrels – Also destroy nests and may compete for nectar sources

Providing dense vegetation cover near feeders and nesting spots helps give hummingbirds refuge from predators. Keeping pet cats indoors reduces unnecessary predation. Installing squirrel-proof feeders can help prevent nectar theft.

Competition with other pollinators may also impact food availability. Invasive species like European starlings often monopolize feeders. Expanding populations of native bees, wasps, sphinx moths and other flower visitors may also compete with hummingbirds for limited nectar supplies, especially if habitat losses concentrate foragers together.

Boosting food sources by planting a wide diversity of flower types that appeal to different pollinators can ease competition pressure.

Efforts to Help Hummingbirds

Although the exact causes are often tough to pinpoint, it appears a mix of factors are contributing to declining hummingbird numbers. Here are some ways individuals and organizations can support these special birds:

Habitat Enhancement

• Plant native flowers, trees, and shrubs to provide nectar and nesting sites
• Avoid pruning flowers in summer and fall to ensure nectar supplies
• Provide water sources like fountains, misters, and drips
• Let dead trees stand as nest sites
• Allow natural leaf litter to accumulate for insect food sources
• Advocate for hummingbird habitat conservation in your area

Reducing Threats

• Keep cats indoors
• Limit pesticide use through natural landscaping
• Install squirrel-proof feeders
• Disinfect feeders to reduce disease spread
• Report signs of diseased birds to help wildlife agencies track outbreaks

Supportive Feeding

• Supplement natural nectar with clean feeders, refreshed often
• Use plain white sugar only, no honey, dyes, etc.
• Site feeders out of reach of predators
• Provide feeding in winter and during migration

Citizen Science

• Join a hummingbird monitoring program
• Report hummingbird sightings to eBird or other databases
• Track activity at your own feeders
• Share photos on social media to expand interest

Hummingbirds are a shared treasure, and community-driven conservation will be key to reversing population declines. Through a combination of habitat improvement, threat reduction, and supportive care, we can ensure these aerial jewels continue gracing our summers for generations to come.

Summary of Factors Affecting Hummingbird Populations

Here is a summary of the key factors explored in this article that may be contributing to declining hummingbird numbers:

A combination of environmental stewardship, conservation programs, and individual actions to make yards and communities more hummingbird friendly can help protect these special birds.

Conclusion

Hummingbirds occupy a special place in many hearts, and it is distressing to see their numbers dropping across North America. The likely reasons are complex, but human-caused habitat degradation and climate change impacts appear to be primary drivers. Reversing these long-term threats will take commitment from policy makers. But citizens can also have an immediate impact by enhancing backyard habitats and helping provide for hummingbird needs.

By planting native flowers, going chemical free, putting up feeders, and spreading awareness, we can give hummingbirds a fighting chance. Their beauty and free spirits inspire so much joy. Focusing effort and care on supporting these tiny creatures will help ensure they continue dazzling us with their aerobatics for generations to come.