How Do Hummingbirds Generate Lift When Hovering?

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How do hummingbirds generate lift when hovering? They keep their bodies in one place in the air by making lift on both the downstroke and the upstroke of each wingbeat. Generalist birds in slow hovering flight generate little upstroke support, while hummingbirds invert their wings to increase upstroke lift. This article explains that mechanism using two peer-reviewed sources, one a comparative study of hovering performance and one a study of a scaled hummingbird wing model. It also states where those sources stop.

Quick answer

• A hovering hummingbird generates about a quarter of the vertical force it needs on the upstroke, which most birds in slow hover do not do.
• It does this by inverting its wings further, so the upstroke also produces lift.
• The wing-model study links a leading-edge vortex that shows high fluctuations rather than a steady form to high lift production.

Why hovering is different from ordinary flight

Hummingbirds and nectar bats are the only vertebrates that are specialized for hovering in front of flowers to forage nectar. That specialization is the reason the question matters.

The comparative study looked at this problem across species. The study compares 20 Neotropical species, and it reports that nectarivorous birds and bats converged on this ability by inverting their wings more than species with other diets.

The upstroke is the surprise

To hover, hummingbirds consistently generate about a quarter of the vertical aerodynamic force required to support their body weight during the upstroke. The same study says that in contrast, generalist birds in slow hovering flight generate little upstroke weight support.

The comparative study ties this to wing position. To hover effectively, hummingbirds invert their wings further to increase upstroke lift, while small bats rely on larger wings.

A second source gives the downstroke side of the picture. Studies of free-flying hummingbirds have found the lift production to be asymmetric between the stroke-halves, where the power stroke, denoted herein as the downstroke, produces up to 75% of the weight support, contrary to insects where wing support is symmetric.

A horizontal wingbeat that mostly makes lift

The comparative study describes a difference in wing motion between hummingbirds and bats. Hummingbirds converged on an efficient horizontal wingbeat to mostly generate lift. Bats, by contrast, rely on lift and drag during the downstroke to fully support their body weight.

The study also reports that nectar bats generate elevated weight support during the upstroke, but that it is much smaller than that of hummingbirds.

Why the study looks at the whole year

The wing-model study starts from a practical point about these birds. As hummingbirds mainly feed while hovering, it is crucial to maintain this ability throughout the annual cycle, especially during flight-feather moult, in which wing area is reduced. The study therefore sets out to quantify the aerodynamic characteristics and flow mechanisms of a hummingbird wing throughout the annual cycle, not only at one moment.

The test object is described as a dynamically scaled wing model. That wording matters for how the results should be read. The measurements describe a scaled wing model, and the sources do not claim a wider measurement across every hummingbird species.

What happens at the wing surface

The wing-model study looked at the flow over a hummingbird wing. It reports that the vorticity concentration that had developed from the wing’s leading-edge differs from the attached vorticity structure that was typically found over insects’ wings. In plain terms, the air swirl on the hummingbird wing is not the same as the swirl seen on an insect wing.

The study describes the difference in shape and behaviour. The vortex is more elongated along the wing chord, and it encounters high levels of fluctuations rather than a steady vortex.

Why does that matter for lift? The study notes that destruction of the leading-edge vortex may strongly diminish the high lift production which is associated with it. In other words, the vortex is part of the lift mechanism, and if it breaks down the lift falls.

How the lift compares with insects

The wing-model study finds that lift characteristics resemble those of insects, however a 20% increase in the lift-to-torque ratio was obtained for the hummingbird wing model.

The study also estimates power. Time-accurate aerodynamic loads were also used to evaluate the time-evolution of the specific power required from the flight muscles.

How we chose

Both sources were chosen because they address hummingbird hovering directly and both are available as full text from PubMed Central. The first is a comparative study of hovering performance in Neotropical hummingbirds and bats. The second is a study of the aerodynamics of a hummingbird wing across the year, with a focus on the flow over the wing.

Both pages were fetched directly and returned full article text. Each claim in this article is tied to a verbatim quote in the research note for this slug. Where a source does not state something, this article leaves it out.

What we could not verify

The sources do not give one universal measurement of lift for every hummingbird species, and the wing study uses a scaled model of a single species. The comparative study covers 20 Neotropical species, so the results do not describe every hummingbird. This article does not claim a lift figure for any species beyond what the sources state.

What the sources do not say

The sources do not explain every detail of the wing motion in a free-flying bird, and they do not give a complete model of the flow for all hovering conditions. The wing-model study reports high levels of fluctuations in the vortex. For the garden side of hummingbird life, see how to attract hummingbirds to your yard, and for a related planting guide, see attracting hummingbirds without a feeder.

Frequently asked questions

Do hummingbirds make lift on the upstroke?

Yes. The comparative study states that to hover, hummingbirds consistently generate about a quarter of the vertical aerodynamic force required to support their body weight during the upstroke. That is more than generalist birds in slow hovering flight, which generate little upstroke weight support.

How do hummingbirds make the upstroke work?

The comparative study says that to hover effectively, hummingbirds invert their wings further to increase upstroke lift. The wing inversion is the key change, and the study contrasts it with bats, which rely on larger wings.

Is the downstroke still important for hovering hummingbirds?

Yes. A second source reports that in free-flying hummingbirds, the downstroke produces up to 75% of the weight support, which is asymmetric compared with insects. The downstroke therefore still does most of the work in many cases.

What is the leading-edge vortex, and why does it matter?

The wing-model study describes a vorticity concentration that develops from the leading edge of the wing. It also says that destruction of the leading-edge vortex may strongly diminish the high lift production that is associated with it. The vortex is therefore linked to lift in the study.

Do bats hover the same way hummingbirds do?

No. The comparative study describes a difference: hummingbirds converged on an efficient horizontal wingbeat to mostly generate lift, while bats rely on lift and drag during the downstroke to fully support their body weight. The two groups reach hovering in different ways.

Sources

• Hovering hummingbird wing aerodynamics during the annual cycle. I. Complete wing. https://pmc.ncbi.nlm.nih.gov/articles/PMC5579086/ (checked 2026-10-28, HTTP 200)
• Biomechanics of hover performance in Neotropical hummingbirds versus bats. https://pmc.ncbi.nlm.nih.gov/articles/PMC6157961/ (checked 2026-10-28, HTTP 200)