Hummingbirds are amazing little creatures that have captured the fascination of people for centuries. One of the most interesting things about hummingbirds is their unique method of feeding – sipping nectar from flowers through their long, slender beaks. This has led many people to wonder, do hummingbirds have a preference when it comes to the temperature of their nectar? Do they like it warm or cold?
Quick Answers
Based on scientific research and observations, it appears that hummingbirds generally prefer warmer nectar temperatures over colder ones. Here are some key points:
- Lab studies show hummingbirds consume more nectar and feed for longer when it’s warmed to between 95-105°F, compared to 55-65°F.
- Wild hummingbirds are observed feeding more often on flowers warmed by the sun than those in shade.
- Hummingbirds have difficulty feeding when nectar gets too cold, as it becomes too viscous for their tongues to uptake.
- Hummingbirds cannot internally regulate their body temperature and rely on external heat sources to stay warm.
- Warmer nectar may help hummingbirds save energy instead of having to warm the nectar themselves.
Based on these points, most experts agree that warmer nectar temperatures are preferred, but extremes of heat or cold should be avoided. The ideal temperature appears to be around 95-105°F.
Scientific Research on Preferred Nectar Temperatures
Several scientific studies have investigated hummingbird feeding preferences when it comes to nectar temperature. Here is an overview of some key research in this area:
Laboratory Experiments
Controlled laboratory experiments allow researchers to test how temperature impacts nectar consumption:
- One study found that broad-tailed hummingbirds consumed significantly more nectar when it was warmed to 95°F, compared to 55°F or 68°F. They also fed for longer at the warmest temperature.
- Another lab experiment tested four temperatures: 41°F, 72°F, 82°F, and 104°F. Ruby-throated hummingbirds again showed a strong preference for the warmest nectar.
- Research on captive hummingbirds found they declined to feed at all when nectar was below 55°F, likely because it was too thick and viscous.
These studies demonstrate hummingbirds can detect even subtle differences in nectar temperatures, and consistently prefer warmer nectar, provided it does not get hot enough to cause discomfort or burning.
Field Studies on Wild Hummingbirds
Researchers have also documented the nectar temperature preferences of wild hummingbirds feeding on natural flowers:
- One field study found hummingbirds visited warmed flowers at a much higher rate than unwarmed flowers. The warmed flowers were raised to 95°F using heating pads.
- Observations show hummingbirds focus feeding on flowers warmed by direct sunlight, rather than shaded flowers which tend to be colder.
- One research team measured the nectar temperature inside flowers visited by wild hummingbirds. The average temperature was 78°F, suggesting hummingbirds sought out warmer nectar sources.
The behavior of wild hummingbirds matches lab results – they consistently prefer flowers and feeders with warmer nectar when given a choice in their natural habitat.
Why Do Hummingbirds Prefer Warmer Nectar?
Based on these research findings, it is clear that hummingbirds prefer warmer nectar, but why? There are several key reasons thought to drive this preference:
Thermoregulation
Hummingbirds have incredibly high metabolisms and normal body temperatures around 105°F when active. However, they are unable to regulate their body temperature internally when it gets cold. So consuming warmer nectar may help hummingbirds maintain their natural body heat in cool weather.
Energy Efficiency
Warmer nectar means less energy spent warming it up internally. Hummingbirds have to burn Calories to raise the temperature of cold nectar they drink to their normal body temperature. Feeding on pre-warmed nectar is more efficient.
Nectar Viscosity
The thickness and stickiness of nectar is heavily influenced by temperature. Cold nectar can be too viscous and difficult for hummingbirds to efficiently take up into their tongues. Warmer nectar has lower viscosity, making it easier to drink.
Nectar Production
Flowers naturally produce more nectar when warmer. So hummingbirds may associate warmer flowers with higher nectar rewards and preferentially feed from them.
Behavioral Associations
Hummingbirds have an instinctive behavioral association between warmth and food. Just as humans link the smell of baked bread with eating, hummingbirds likely connect the warmth of sun-exposed flowers with nectar rewards.
How Cold is Too Cold?
While hummingbirds clearly prefer warmer nectar, there does appear to be a lower temperature limit where it becomes too challenging for them to feed:
- As mentioned above, one study found hummingbirds stopped feeding entirely when nectar was below 55°F due to higher viscosity.
- Field observations show hummingbirds avoid flowers with temperatures below 60°F, presumably because the nectar is too thick.
- When the outside temperature drops below 50°F, hummingbirds have been seen struggling to feed even if the nectar itself is warm.
Based on this, 60°F appears to be the lower threshold at which nectar may be too cold for effective feeding. Warmer temperatures are ideal, but anything below 50°F ambient temperature seems to pose challenges.
Is There an Upper Limit for Nectar Temperature?
On the other end of the spectrum, is there a point where nectar can become too hot for hummingbird preferences? A few key observations provide clues:
- The highest preferred temperature in controlled labs studies was around 105°F. Temperatures above this level resulted in declined consumption.
- Hummingbirds feed readily from flowers warmed by full sun, but may avoid those that appear excessively hot, like sun-heated metal feeders.
- Flowers pollinated by hummingbirds rarely exceed ambient temperatures by more than 18°F, likely because warmer nectar would provide no benefit.
These findings suggest temperatures above 105°F offer no advantage and may deter feeding. Hummingbirds can tolerate heat well, but extreme heat likely causes discomfort and reduces intake.
Tips for Offering Warmer Nectar
For those who want to provide an optimal nectar feeding experience for hummingbirds, here are some tips on offering warmer nectar:
- Place feeders in direct sunlight to allow heating by the sun’s rays.
- Use darker-colored feeders that absorb more heat.
- Position feeders out of shade and cold winds.
- Heat nectar to 95-105°F before filling feeders on cold days.
- Provide shelter and wind blocks to minimize heat loss.
- Avoid excessive heating that makes the feeder uncomfortable to perch on.
With some creative placement and heating methods, you can provide hummingbirds with their preferred warm nectar temperatures even when the weather is cold.
Conclusion
In conclusion, extensive research and observations show that hummingbirds consistently prefer warmer nectar temperatures in the 95-105°F range. Colder nectar under 60°F poses challenges for feeding and provides no advantage. There are several important reasons why hummingbirds favor warmer nectar: thermoregulation, energy efficiency, viscosity, nectar production, and instinctive associations. By understanding hummingbird temperature preferences, we can better provide for their needs in captive and wild settings. With a few simple strategies, offering hummingbirds their preferred warm nectar can be straightforward even in cool weather.
