Rivoli's Hummingbird Guide (Eugenes fulgens)

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Reina loves watching birds and learning new ways to identify them. When she started her own lawncare company, she fell in love with our feathered friends. Currently, she is learning how to identify them from their song! She loves to share her tips, tricks, and product recommendations here on Birding Insider; you can get the most out of your birding hobby!

Taxonomy

Now that the distinction between the Magnificent Hummingbird and Rivoli’s HUmmingbird has adequately confused you let’s take a deeper look at the taxonomic classification of this bird.

Eugenes fulgens belongs to the Lampornithini tribe of the subfamily Trochilinae within the family Trochilidae. This tribe is otherwise referred to as “Mountain Gems.”

The three tribes of Tronchilidae are:

Lampornithini, informally known as mountain gems.
Mellisugini, informally known as bees,
Trochilini, informally known as emeralds.

Mountain Gems contains eighteen different species of hummingbirds that are classified into seven different genera.

Fitting for a bird named after a duke, the Eugenes is translated to mean high born, while fulgens means glittering or gleaming. Even at a brief glance, this name makes perfect sense.

How to Identify a Rivoli’s Hummingbird

Size and Shape

Rivoli’s Hummingbird is known for being one of the largest hummingbird species in the United States, behind the Blue-throated Mountaingem by only a half inch. Their overall length ranges from 4.3 to 5.5 inches, weighing 6 to 10 grams. Wingspands are, on average, about 7 inches. Males are slightly larger than females. This hummingbird has a long and straight or slightly decurved bill. Lengthy wings are met with its slightly forked tail.

Color Pattern

Male Rivoli’s are dark in appearance when the sun is not glimmering upon their stunning iridescent feathers. They have black heads with a small white eye patch, green bodies, and dark tails with brown to bronze accents. In the sunshine, males show off their violet crowns, blue-green gorgets, and glittering green feathers that adorn most of their bodies. The way the violet crown contrast with their black head and cheek and the white eye spot is absolutely gorgeous.

In typical hummingbird fashion, females are less flashy but still total showstoppers. Bodies are brown-green with grayish bellies and underparts. A small white streak begins behind the eye, extending to the nape.

eugenes fulgens — Image source: All about Birds

Where Does a Rivoli’s Hummingbird Live: Range and Habitat

Rivoli’s Hummingbird is found in mountainous areas across the southwestern United States, extending through Honduras and northern Nicaragua. Elevations between 5,000 and 9,000 feet are preferred by this hummingbird. Pine-oak forests and cloud forests are their primary habitats, with a tendency to stay close to the forest edge or in clearings.

If you’re wondering where to look within the United States, sightings are most frequent in southwestern New Mexico and southeastern Arizona. Some researchers claim summer sightings near the Chisos Mountains of Texas. So add Rivoli’s Hummingbird to the increasingly long list of birds to look for while in Big Bend National Park, though do avoid it in the summer months.

It’s common to find this bird in the mountains of Costa Rica. Other areas to look for this bird are shady canyons and streamsides near pine-oak, sycamore, or maple forests.

Migratory in part of its range, Rivoli’s Hummingbird spends its winters in Mexico, making its way south to Panama.

Rivoli’s Hummingbird Diet and Feeding

Rivoli’s Hummingbird has a diet that is typical of most hummingbird species: nectar and insects. A heavy intake of calories is needed to keep their bodies moving at high speeds. Hummingbirds need to consume around half their body weight each day. They will visit thousands of flowers but still need to consume ample amounts of insects in order to get decent nutrition. Interestingly enough, Rivoli’s Hummingbird consumes more insects than other North American species.

Insects are gleaned, which basically means plucked in birding terms, from plants and foliage. Hummingbirds can also skillfully catch insects while in an effortless mid-air hover.

Nectar is still a vital source of energy. Rivoli’s elongated slender bills aid them as they drink nectar from long tubular flowers that other hummingbirds cannot access, licking it up 13 times per second!

Traplining is a term used to describe the foraging style of Rivoli’s within the United States. Traplining is the action of moving rapidly between various patches of blooming and nectar-rich flowers. Spacing out visits give the flowers time to produce more tasty sweet nectar for the bird.

This also gives birds the opportunity to find plants that are particularly productive at producing nectar. When they hit the nectar jackpot, an aggressive territorial defense is used, typically by males, to keep other birds from stealing their liquid gold.

Common plants that Rivoli’s feed on are:

Agave americana
Thistles
Butterfly bushes
Rose of Sharon
Bellflower
Jacob’s ladder
Vervain
Beardlip penstemon
Lion’s ear
Lemmon’s sage
Red columbine
Bouvardia

Rivoli’s Hummingbird Breeding

In the spring and summer, Rivoli’s Hummingbirds living within the northern portion of their range, such as the Chihuahuan desert, focus their efforts on nesting. May through July is the primary breeding season throughout the rest of their range, but biologists believe that Rivoli’s occupying El Salvador may breed year-round.

The breeding season is synchronized with the blooming of flowers and increased quantities of insects. This ensures ample food and energy sources are available to accommodate the entire family.

Rivoli’s Hummingbirds do not have any specific differences from other hummingbirds regarding breeding rituals and practices (that we know of at this point in time), so let’s look at what we do know!

Throughout the family Trochilidae, breeding is non-monogamous and, aside from the actual copulation, completely independent. Males put on a show in their chosen territory to attract females. This display typically involves males climbing thirty to sixty feet in the air and diving down in a “U” formation. Some species sing in addition to the aerial display. Females may choose to mate with the male and nest in or near his territory, which the male will defend aggressively.

Both male and female hummingbirds may mate with multiple partners, but it is the sole responsibility of the female to choose a nesting site, build the nest, incubate, and raise young.

Rivoli’s Hummingbird Nesting

Female hummingbirds seek out horizontal branches that are streamside in which to build their nests. A nest may be located anywhere from 10 feet to 89 feet off the ground, with the optimal distance being 20 feet.

After selecting a site, the female gets to work building her nest. She collects a variety of materials, such as moss, feathers, animal hair, plant fibers, and leaves. A small cup is constructed that is about 2.2 inches wide by 1.7 inches tall. The nest is only 1 inch deep, but this next move is a game changer…

She wraps the nest in spiderwebs, which allows the cup to expand as the chicks grow. Additionally, she attaches lichen to the exterior to camouflage the nest from potential predators and male hummingbirds. If a male visits her at the nest, his bright colors and boisterous behavior will likely tip off more unwanted guests.

Rivoli’s Hummingbird Eggs

The average clutch size for Rivoli’s Hummingbird is two to three white oval eggs which the female incubates by herself. She will quickly venture off to source food for herself over the 15 to 19-day incubation period.

Once the eggs hatch, the tiny birds are blind and featherless. Mother bird feeds the young around the clock by regurgitating insects, sometimes mixed with nectar, directly into the nestlings’ bellies using her long bill.

Hummingbirds are known for their short brooding periods. Rivoli’s Hummingbirds are no different. On cold nights, mama birds may leave the nestlings on their own, and after one or two weeks, chicks leave the nest to fend for themselves fully.

Rivoli’s Hummingbird Population

No information is available regarding an estimated population size for Rivoli’s Hummingbirds, but conservationists believe the population is healthy. This is because there have been no signs of declining populations.

The last known data obtained was in 2017 for both Rivoli’s Hummingbirds and Talamanca Hummingbirds, which were grouped together as Magnificient Hummingbirds until that time. When combined, their estimated breeding population was about 2 million.

Rivoli’s Hummingbirds currently have a 12 out of 20 on the Continental Concern Scale, which indicates them as a species of low concern.

If you’re unfamiliar with the Continental Concern Score, it is a system designed to assign a numerical score to avian species in the continental United States, Canada, Mexico, and various waterfowl. Population size, breeding distribution, nonbreeding distribution, vulnerability, and threats are considered factors.

Rivoli’s Hummingbird Habits

Hummingbirds are some of the smallest birds but are extremely fast. They reach speeds of nearly 30 miles per hour. During courtship dives performed by male hummingbirds, they may reach speeds of 45 miles per hour. It would be best if you did not interfere with nesting hummingbirds in your area for this reason. They might seem cute, but they can still do some serious damage.

But wait, there’s more! Hummingbirds’ have heartbeats of 225 beats per minute, and that’s their resting heart rate. In motion, their average heart rate is 1,200 beats per minute. Their wings beat anywhere from 70 to 200 times per second to reach this impressive number, depending on their movement. No wonder they need to eat every 2,000 insects per day.

You may have noticed, but the agile bodies of hummingbirds aren’t covered with very many feathers. The feathers they do have do not provide them with much warmth. To counteract this issue, hummingbirds have a secret weapon called torpor. This is a deep sleep-like state that allows them to reduce their metabolism to just one-fifteenth of their normal rate.

Their resting heart rate of 225 beats per minute drops to just 50. The hummingbird will choose a comfortable and safe location before entering torpor. This state conserves 60% of the hummingbird’s energy.

Hummingbirds in torpor will look like they are sleeping or even dead. Common body positions in torpor are pointed beaks and puffed feathers. They may also hang upside down. You should never disturb hummingbirds in a torpor state. Not all hummingbirds survive torpor if they enter it in a weakened state. Upon waking up, recuperating lost energy through food is a must to recover from the incredible process their body just underwent.

Rivoli’s Hummingbird Predators

While these predators aren’t specific to only Rivoli’s Hummingbirds, it is a concise collection of threats that most hummingbirds face on a regular basis.

Cats, both feral and domesticated, will slink around feeders waiting for a chance to strike. Larger birds, such as hawks, owls, crows, gulls, and more, have been known to swoop in and snatch up unsuspecting hummingbirds. Snakes, frogs, and even some fish have been known to catch a hummingbird in their clammy clutches. Insects like spiders and praying mantises are likely also predators. Yuck!

Animals that may invade nests, eating eggs and young, are snakes, squirrels, chipmunks, and corvids.

Do Your Part to Save Hummingbirds

Want to know the number one killer of hummingbirds? Spoiled sugar water, dirty and unkempt hummingbird feeders, and commercial nectar. So let’s dive into a few hummingbird care tips so we can all do our part to aid populations in our area.

Hummingbird Feeder Care

Feeding hummingbirds is a simple and affordable pleasure that most birders enjoy regularly, but it’s easy to get caught up in the magic of these little gems and forget that by putting that feeding in our yard, we agreed to keep the feeder full, safe, and clean.

Hummingbird feeders should be placed in partial shade. Direct sunlight and high temperatures turn sugar water into a fermented toxin that can easily kill hummingbirds stopping by for a drink. Discard any unused nectar and start fresh at least once per week in normal temperatures. Feeders should be emptied and cleaned twice weekly with hot water during warmer months. You may also use a weak vinegar solution. Avoid using dish soap, mild or not that could leave residues and chemicals behind.

Employ the aid of a bottle brush to scrub nooks and crannies on the feeder. You should completely disassemble the feeder when cleaning it and soak any small pieces in hot water to make for easier cleaning.

Hummingbird Nectar Guidelines

Did you know that while hummingbirds are attracted to the color red, a red dye can turn delicious and energizing sugar water into poison? Never add any kind of food coloring or dye to hummingbird nectar. Additionally, you should avoid commercial hummingbird food.

Many commercial hummingbird foods contain additives, preservatives, and unnecessary ingredients. It’s also just a plastic jug of diluted sugar…so think about the earth too! Instead, make your own sugar water in just a few simple steps.

rivoli humming bird — Image source: All about Birds

Hummingbird Nectar Recipe

Take one part refined white sugar and add it to four parts hot tap water. You may boil water, but remove it from heat before adding sugar.

Ex. 1 cup refined white sugar, 4 cups water.

Never use any other type of sugar like brown sugar, molasses, honey, raw sugar, or sugar substitutes. Never add red coloring, natural or otherwise. Never add anything else to the mixture!

Once the sugar water has reached room temperature, fill feeders and store any extra in the refrigerator in a sealed container for up to one week. Discard any unused nectar after seven days and brew a fresh batch to be on the safe side.

The best part about feeding hummingbirds, aside from watching their joy and excitement, is that it is a relatively low-cost hobby compared to purchasing seeds. One large bag of refined white sugar, currently about $4, can supply you and hummingbirds with months of nectar.

You don’t need an expensive feeder, either. A simple plastic feeder is all you need to get started. Just make sure it has some red on it, and the hummingbirds will find you! Again, never use red hummingbird food. You will see this used in product images as a marketing tool to sell you commercial hummingbird food. Instead, head to the baking aisle and purchase a bag of sugar.

Rivoli’s Hummingbird Lifespan

The oldest lifespan for a Rivoli’s Hummingbird is recorded to be 11 years and 2 months old. This was the age of a male Rivoli’s Hummingbird that was banded in Arizona.

FAQ

Question: Where does the magnificent hummingbird live?

Answer: In 2017, the Magnificent Hummingbird was split into two species, Rivoli’s Hummingbirds and Talamanca Hummingbirds. These species live in pine-oak forests across mountainous climates of the southwestern United States, extending into Central America.

Question: What is the largest size hummingbird?

Answer: In North America, the largest hummingbird is the Blue-throated Mountain Gem. This bird is 5.5 inches, which is only a half inch larger on average than Rivoli’s Hummingbird. Across all continents, the giant hummingbird or Patagona gigas of western South America is 8 inches long.

Question: How big is a magnificent hummingbird?

Answer: Rivoli’s Hummingbird, formally known as the Magnificent Hummingbird, are around 4.3 to 5 inches in length, with a 7-inch wingspan.

Question: Are Anna’s hummingbirds aggressive?

Answer: Anna’s Hummingbirds are known to be a bit more territorial than other species. Males take their duty very seriously and fend off any unwanted guests such as bees, moths, and other birds.

Research Citations

Looking for more interesting readings? Check out:

Rivoli’s Hummingbird Guide (Eugenes fulgens)