How do hummingbirds show aggression?

Hummingbirds are known for their small size and beautiful, iridescent plumage. However, behind their delicate exterior lies an aggressive nature when it comes to defending resources. Hummingbirds are very territorial and will act aggressively to defend their food sources, nesting areas, and mating rights.

Defending Food Sources

Flowers and artificial nectar feeders are critical resources for hummingbirds. They will aggressively defend these food sources from other hummingbirds or animals. A dominant male will often claim a particularly abundant food source, such as a backyard feeder, as its territory. When another hummingbird attempts to feed, the dominant male will display aggressive behavior to scare it away. Here are some ways hummingbirds show aggression over food sources:

• Chasing – A hummingbird defending a food source will chase intruders for short distances or directly into another object.
• Dive bombing – The defending bird will make steep, swift dives toward the intruder.
• Vocalizations – Males defending a food source will make shrill sounds or chirps to signal their dominance.
• Threat displays – A hummingbird may flare out its throat feathers or splay its tail to appear larger and more threatening.

These behaviors help establish a “pecking order” at food sources, with one dominant male controlling access to the feeder or flower over subordinate males or females. Aggression tends to increase around artificial feeders, especially when they are first introduced, as the birds compete for this rich new resource.

Protecting Nest Sites

Male hummingbirds are highly aggressive when it comes to protecting their nesting sites. Here is how they react to perceived threats:

• Dive bombing – Males will dive bomb any animal or human that gets too close to the nest.
• Intimidation displays – Similar to behaviors at food sources, males may flare their tail and plumage to appear more imposing.
• Vocalizations – Loud chirping is used to signal that the intruder should retreat from the protected area.
• Contact attacks – If an intruding male hummingbird gets too close to the nest, the defending male may directly attack it and attempt to stab it with its beak.

Interestingly, females do not actively defend the nest. They rely entirely on the male’s aggressiveness to protect the nesting site from threats. His aggressive behavior tends to increase as eggs are laid and incubating begins.

Competition for Mates

Male hummingbirds also show aggression when competing for female mates. Here are some competitive behaviors exhibited by males:

• Courtship displays – Males will perform elaborate courtship rituals to attract females, including dives, zigzags, and flying in loops while vocalizing.
• Fighting – Males will physically fight using their beaks and claws to attack other males.
• Displays of dominance – Dominant males will chase subordinates and perform intimidating displays.
• Mate guarding – A male will follow and remain close to a chosen female to prevent other males from mating with her.

These behaviors allow dominant males to gain access to the most desirable and receptive females.

How Aggression Differs by Species

All hummingbird species exhibit some degree of aggression, but certain behaviors and intensity varies between species. Some examples:

In most species, males are generally more aggressive than females. However, there are always individual variations, with some exceptionally aggressive females and less dominant males.

Why Hummingbirds Are So Aggressive

There are several evolutionary reasons why hummingbirds exhibit aggressive behavior:

• Competition for limited resources – Flowers and nectar are only available in limited supplies, especially certain favored species. Aggression helps dominate these resources.
• Danger from predators – Hummingbirds are vulnerable to predators at all life stages from eggs to adults. Aggressiveness helps protect nest sites and drive away potential threats.
• Attracting mates – Males that can out-compete others demonstrate their physical superiority. This attracts females looking for fittest mate to produce offspring with.
• Survival adaptation – Small size means hummingbirds must adopt aggressive strategy to gain resources needed to survive and successfully reproduce. It’s a necessary behavior for the species.

While aggression seems contrary to hummingbirds’ delicate appearance, it is a critical adaptation for their survival. The behaviors have evolved over thousands of generations to help them thrive despite their small size.

Aggressive Interactions with Other Species

Hummingbirds will show aggressive behavior towards other species that interfere with their resources. Some common aggressive interactions include:

• Attacking woodpeckers, orioles, and squirrels that approach their feeders
• Fighting bees or wasps that are also attracted to nectar sources
• Mobbing larger birds, like crows or jays, that get near their nest
• Chasing butterflies, insects, and bats from their feeders and flowers

Despite being much smaller in size, hummingbirds will boldly attack and chase larger animals that represent a threat. They will also show curiosity and aggression towards bright colored objects or clothing if they perceive them to be rival hummingbirds entering their territory.

Interesting Aggressive Behaviors

Here are some intriguing examples of hummingbird aggression:

• A dominant male was observed killing another male by stabbing it repeatedly with its beak after a midair collision at a feeder.
• Some males will sneak attack other hummingbirds by diving at them with the sun at their backs to conceal their approach.
• In a phenomenon called “bill fencing,” males will lock beaks and push back and forth in a test of strength. They also grip each other’s bills and spin in the air.
• Females have been documented dive bombing humans and animals, such as hawks, owls, and crows, that get near their nests while the male is absent.

These examples demonstrate the fierce extent hummingbirds will go to establish dominance and protect vital resources.

Aggressive Behavior in Captivity

Hummingbirds kept in zoos, aviaries, or as pets still exhibit their natural aggression toward humans:

• Charging and vocalizing when caretakers approach to clean cages or refill feeders
• Dive bombing at people as they walk through aviary exhibits
• Fighting with caretakers and sometimes clinging to their hair or clothing with feet and beak
• Becoming highly territorial if housed in same cage as another hummingbird

Their aggression can make hummingbirds challenging to keep in captivity. Care must be taken to minimize territorial behaviors and introduce any new birds gradually.

Tips for Dealing with Aggressive Hummingbirds

Here are some tips to handle aggressive hummingbirds around your home:

• Use more than one feeder so multiple birds can feed
• Select darker colored feeders that blend into background
• Place feeders out of sightlines from each other
• Use feeders with perches so dominant birds can’t hover guard it
• Spread out flower gardens so territories don’t overlap
• Back away slowly if dive bombed; don’t swing at them
• Remove feeders for a few days to displace territorial birds
• Avoid bright clothing that may be mistaken for other birds

With some adjustments, you can enjoy watching hummingbirds safely even with their aggressive tendencies.

Conclusion

Hummingbirds display a range of aggressive behaviors centered around defending resources critical to their survival, such as food sources, nesting sites, and mates. Males are especially aggressive as they compete for territories and females. Aggression varies in intensity between species but serves an important evolutionary purpose for these tiny, delicate birds. With an understanding of their behaviors, we can reduce unwanted aggression that arises from our artificial feeders and gardens. While their aggression seems contrary to their appearance, it is simply a survival strategy that hummingbirds rely on despite their diminutive size.