Hummingbirds are amazing little birds that have evolved some incredible abilities. One of the most fascinating is their use of spider silk to build their tiny nests. But where do hummingbirds get spider silk from? Here we will explore the ingenious methods hummingbirds use to collect spider silk and weave it into cozy, stretchy nests.
Why Do Hummingbirds Use Spider Silk?
Hummingbirds build very small, cup-shaped nests to hold their eggs and raise their young. Because their nests are so tiny, the materials used need to be stretchy and elastic so the nest can expand as the baby birds grow. Spider silk is perfect for this – it is an incredibly elastic and strong material that can be stretched to up to 4 times its length without breaking.
Spider silk is lighter and more flexible than most plant fibers like cotton or paper. It also readily sticks to itself, so the hummingbird can weave the silk strands together into a cohesive and stretchy cup-shaped nest. Spider silk also expands when wet and then shrinks as it dries, which allows the nest to survive heavy rains and retain its shape. Additionally, spider silk is covered in tiny barbs that allow the silk strands to felt together into a soft mat, rather than falling apart into individual threads.
For all these reasons, spider silk makes an ideal elastic and durable building material that hummingbirds can use to create cozy, flexible nests for their young.
Methods Hummingbirds Use to Collect Spider Silk
Hummingbirds have evolved some very clever methods to gather the spider silk they need to build their tiny nests. Here are some of the main techniques they use:
Picking up loose strands
Hummingbirds will pick up any loose bits of spider silk they find dangling or caught on plants and branches. As spiders move through vegetation they often leave behind bits of silk. The hummingbird uses its precision beak to gather these loose strands and tuck them into special grooves on its tongue.
Harvesting directly from spider webs
Hummingbirds have been observed harvesting silk directly from spider webs. They use their beaks to pull and gather strands of silk from the orb webs that spiders spin. The spider silk is once again stored in their tongue grooves.
Stealing silk from spider egg sacs
One ingenious but gruesome strategy is for hummingbirds to steal silk directly from spider egg sacs. Female spiders spin thick, protective casings out of silk to house their eggs. The hummingbird will use its beak to snip into these sacs and take gathered clumps of the thick silk.
Following spiders and gathering the silk trail
Hummingbirds will often follow spiders as they move through the vegetation. The spider leaves behind a trail of thin silk known as a dragline. As the spider moves, the hummingbird gathers up this freshly laid dragline silk.
How Hummingbirds Weave Spider Silk into Nests
Once the hummingbird has gathered a substantial amount of spider silk, it then has to weave this silk into a complete nest. This is a complex process that relies on the unique properties of the hummingbird’s body.
The hummingbird starts by gathering the spider silk strands and binding them together using droplets of sticky saliva. The saliva causes the silk fibers to adhere to one another.
Next, the hummingbird uses its precision beak to twirl and loop the silk strands around each other, similar to how a person braids hair. This twisting action causes the strands to tightly bind and weave together.
As it works, the hummingbird uses its feet and body to pull and tension the silk strands. The tension helps the fibers stick together and compacts them into a tight weave. The bird’s feet are specially adapted to easily grip and tug on the silk.
The hummingbird’s unique bifurcated tongue is also a key part of the weaving process. By quickly moving the split tips of its tongue in and out, the bird can loop, knot, and thread the silk fibers.
Using all these techniques, the hummingbird deftly weaves the gathered spider silk into a tidy cup nest shape. The final nest is an intricate woven blanket of silk that is incredibly elastic and durable – perfect for housing and protecting hummingbird eggs.
Notable Examples of Spider Silk Gathering
Here are some specific examples and observations of hummingbirds gathering spider silk in the wild:
Black-chinned Hummingbird
The Black-chinned Hummingbird has been observed gathering spider silk from over 15 different types of spider webs. They preferentially target webs built by larger spiders, which produce thicker silk strands.
Calliope Hummingbird
Researchers watched Calliope Hummingbirds steal silk from the egg sacs of bowl and doily spiders. The birds used precision pecking to open the sacs and remove gathered clumps of thick silk.
Anna’s Hummingbird
Anna’s Hummingbirds often follow Western black widow spiders as they spin new webs. The birds gather the fresh draglines before the spiders have a chance to incorporate them into the web.
Rufous Hummingbird
One study found that Rufous Hummingbirds preferred to gather silk from the webs of smaller spiders, possibly because these finer fibers are more suitable for tiny nest construction.
Unique Hummingbird Adaptations for Gathering Silk
Hummingbirds have evolved some remarkable physical adaptations that allow them to effectively gather and weave spider silk:
Needle-sharp precision beaks
A hummingbird’s long, tapered beak allows them to delicately pluck and pull spider silk strands from webs without destroying the web structure.
Cleverly bifurcated tongues
The hummingbird’s unique split tongue acts like a pair of tweezers, adeptly gathering, threading and knotting silk strands.
Specialized silk gathering grooves
Grooves along the hummingbird’s tongue allow it to efficiently collect and transport gathered silk strands.
Strong feet and legs
Hummingbirds have proportionally large and powerful feet that give them a strong grip on silk strands, allowing them to pull and tension the fibers.
Impact on Spider Populations
Researchers have looked at whether hummingbirds gathering silk from webs has any negative impact on spider populations. The conclusions are that hummingbird silk harvesting does not significantly harm spider communities:
- Most spiders quickly remake any damaged areas of their webs
- Silk gathering does not appear to increase the risk of spiders being preyed upon
- Hummingbirds take only a very small percentage of available silk
- Webs may be abandoned or rebuilt on a daily basis already
So although hummingbirds occasionally damage spider webs during silk gathering, they do not threaten spider communities or greatly impact spider survival. The spiders are able to quickly repair and rebuild any damaged webs.
Conclusion
Hummingbirds have evolved some remarkable abilities to gather the spider silk they need to build their tiny, elastic nests. Using precision beaks and clever tongues, they are able to carefully remove and collect silk from webs and egg sacs. The birds have specialized tools and techniques for twisting and weaving the silk into cozy, durable nests. While spiders may lose some silk to hummingbirds, the silk gathering does not appear to negatively impact spider populations overall. The relationship between hummingbirds and spiders provides a fascinating example of nature’s clever innovations.
