Hummingbird moths, also known as hawk moths, are a group of fast-flying insects that get their name from the hummingbird-like way they hover in front of flowers when feeding on nectar. While there are hundreds of different species of hummingbird moths found around the world, only a handful of species are regularly seen in Ireland. The most common hummingbird moth species found in Ireland is the hummingbird hawk-moth (Macroglossum stellatarum). This species migrates to Ireland in the summer months from southern Europe and North Africa. Other less frequently encountered species in Ireland include the silver-striped hawk-moth (Hippotion celerio), the convolvulus hawk-moth (Agrius convolvuli), and the bedstraw hawk-moth (Hyles gallii).
Are hummingbird moths native to Ireland?
Hummingbird moths are not native to Ireland. The species found in Ireland are migratory and do not overwinter or breed here. The hummingbird hawk-moth is widespread across Europe, Asia, and Africa and breeds in continental Europe and North Africa. Each year in late spring and summer, adult moths migrate northwards to take advantage of warmer weather and an abundance of nectar-producing flowers. Ireland’s relatively mild climate in summer makes it a suitable temporary home for breeding and feeding. However, as winter approaches, the moths migrate south again to overwinter in warmer regions. This annual migration is why hummingbird moths are present in Ireland only from late spring through early autumn.
What time of year are they most commonly seen?
Hummingbird moths are most abundant in Ireland in late summer and early autumn between the months of July and September. Some individual moths may arrive as early as late May or June, but their numbers peak in August and September. This corresponds with the warmest time of year in Ireland when many flowering plants are in bloom, providing an excellent source of nectar for the moths. Numbers start to decline in October as the weather cools and the moths begin their southern migration for the winter. Sightings become very rare by November. The following table summarizes the main months when hummingbird moths are present in Ireland:
| Month | Hummingbird Moth Sightings |
|---|---|
| January-April | Rare or absent |
| May | Possible early sightings |
| June-July | Sightings increasing |
| August-September | Peak sightings |
| October | Sightings decreasing |
| November-December | Rare or absent |
Where in Ireland are they found?
Hummingbird moths can be found throughout the Republic of Ireland and Northern Ireland wherever there are abundant flowers providing nectar. However, they tend to be most frequently encountered in southern and central regions where the climate is milder. Some key areas where hummingbird moth sightings are regularly reported include:
– Coastal regions – The southern and western coastal areas particularly around Cork, Kerry, Clare, and Galway provide ideal habitat.
– Gardens – Gardens with flowering plants in Leinster, Munster, and Connacht often attract the moths.
– Parks and open meadows – Areas like Phoenix Park in Dublin and meadow regions in Cork and Tipperary host the moths.
– Nature reserves – Killarney National Park and the Burren region are prime hotspots for sightings.
Sightings are less frequent in cooler northern and eastern inland areas. But on warm days, the moths can be observed feeding anywhere there are flowers, even in northern counties like Donegal, Cavan, and Monaghan.
What plants do they feed on?
Hummingbird moths feed on the nectar from a wide variety of flowering garden plants and wildflowers. Some of the most common food sources include:
– Buddleia – The blooms of this butterfly bush are a magnet for hummingbird moths.
– Lavender – The tubular purple flowers provide an excellent nectar source.
– Red valerian – Another tubular flower favoured by the moths.
– Petunias – A popular garden annual that attracts hummingbird moths.
– Honeysuckle – The nectar-rich tubular flowers appeal to the moths.
– Thistles & knapweeds – These wildflowers provide food in meadows and fields.
– Clovers – The nectar draws the moths to these flowering plants.
– Marjoram & oregano – Both culinary and ornamental varieties are fed on.
– Verbena bonariensis – Tall verbena flowers are magnets for hummingbird moths.
The moths are strongly attracted to flowers with abundant, exposed nectar that they can easily access while hovering. Tubular flowers seem to be their favourites.
How to attract hummingbird moths to a garden
Here are some tips to make your garden more attractive to hummingbird moths if you want to observe these fascinating insects:
– Plant nectar-rich flowers they feed on like buddleia, lavender, valerian, verbena, and clovers.
– Have a continuous bloom from early summer through fall by planting early, mid, and late-blooming flowers.
– Choose brightly colored flowers like reds, oranges, pinks, and purples which attract the moths.
– Arrange plants in dense clumps and drifts rather than spaced apart.
– Include some night-scented flowers like nicotiana or jasmine that release fragrance at dusk when moths are active.
– Provide shrubby areas and tall plants for the moths to rest on during the day.
– Position feeder flowers out in the open in sunny spots where the moths can easily fly to them.
– Avoid using pesticides which could be harmful to the moths and other pollinators.
– Install a shallow water feature or dripping tap so the moths can drink.
– Consider leaving areas of long grass and wildflowers where the moths may also find food.
What is the lifespan of a hummingbird moth?
The lifespan of a hummingbird moth varies by species, but they generally only live for a few months as adults. In the case of the hummingbird hawk-moth that migrates to Ireland, their expected adult lifespan is approximately 2 to 6 weeks on average.
Here is a summary of the typical hummingbird hawk-moth lifespan:
– Egg stage – About 10 days after being laid on host plants like bedstraw, galium.
– Caterpillar stage – Around 3 weeks feeding on host plants.
– Pupal stage – Roughly 2 weeks transforming in a cocoon.
– Adult stage – Between 2-6 weeks living as an adult moth feeding on nectar.
– Total lifespan – Approximately 6-8 weeks from egg to death as an adult moth.
So the adult moths that arrive in Ireland in mid to late summer likely only have a few weeks to feed, mate, and lay eggs on host plants before they die. Their migration to Ireland represents a significant portion of their total adult lifespan.
Do they migrate in groups or individually?
Hummingbird moths primarily migrate individually rather than in coordinated groups or swarms. There is no evidence that the moths actively congregate for migration. Instead, migration appears to be initiated largely by individual moths responding to environmental cues and stimuli such as changing day length, temperatures, and food availability. When conditions become unfavorable where they emerged as adults, this seems to trigger their individual innate drive to migrate to areas with more favorable resources and climate.
However, some aspects of their migration may involve incidental groupings. Moths emerging around the same time in a given area may end up migrating concurrently in loose aggregations. And moths may arrive en masse in a particular area if environmental conditions have made it an ideal feeding or breeding spot. But migration does not involve the type of coordinated, synchronous behavior seen in some migratory birds or insects like monarch butterflies. Essentially each moth makes its own autonomous decision to migrate based on internal and external signals. So while many moths may migrate in the same direction around the same time, they do so as individuals rather than a collective group.
How far do they migrate? What is their range?
The migration distances covered by hummingbird moths can be quite extensive considering their small size. The hummingbird hawk-moth is known to migrate up to 1,000 miles (1,600 km) or more one-way from its breeding grounds in places like North Africa, Europe, and west Asia to summer feeding grounds across Europe, Scandinavia, the British Isles, and as far north as Alaska and Iceland.
In general, the species has an expansive range that covers:
– Africa – Northern Africa, sub-Saharan west Africa, the Canary Islands
– Europe – All countries from the Mediterranean north to Scandinavia and Iceland
– Middle East – Turkey, Israel, Jordan, Lebanon
– Asia – India, Russia, China, Korea, Japan
Within this broad range, individual moths may migrate several hundred miles north in the spring to breed and feed before returning south in the fall. The longest one-way migrations are typically around 600-1,000 miles. Given the short 2-6 week adult lifespan, this represents an astonishing migration feat for such a small, delicate insect. Their ability to fly long distances at speeds up to 12 mph (19 kph) with minimal resting allows them to migrate so swiftly and extensively.
Do they migrate during the day or night?
Hummingbird moths generally do most of their migrating during daylight hours rather than at night. This is likely related to two key factors:
1. They rely heavily on visual cues for navigation during migration. Like birds, the moths seem to orient themselves using landmarks and the position of the sun. These visual guides are unavailable at night.
2. Their key food source is flower nectar which is primarily available during the day. The moths need to periodically refuel on nectar during migration, so night migration would cut off their access to food.
However, the moths do appear to have some ability to navigate and migrate at night as well. On warm, clear nights with a bright moon, they may continue migrating overnight. And on overcast days when visual cues are reduced, they seem able to partly compensate by migrating at night. Their large, highly sensitive eyes give them reasonably good vision even in low light. But in general, maximum migration activity occurs during sunny daytime hours. At night, they tend to rest rather than migrate.
How fast and high do they fly while migrating?
The airspeed of migrating hummingbird moths has been measured directly via wind tunnel tests and radar tracking. Their cruising airspeed is typically in the range of 10-12 mph (16-19 kph) with a maximum speed of around 15 mph (24 kph) during burst flight. This rapid speed allows them to cover long distances relatively quickly during migration.
In terms of altitude during migration, observations and radar studies indicate hummingbird moths generally fly at relatively low elevations below 1,000 feet (300 meters). However, some individuals have been recorded migrating much higher up to 10,000 feet (3 km) or more on mountain passes. Flying at higher altitudes may allow them to take advantage of faster wind speeds to aid their migration. But most migration activity seems to occur at lower altitudes, likely due to the greater availability of food sources and navigation landmarks.
The moths sometimes pause their migration to rest on flowers, trees, or structures. But remarkably they are able to fly continuously for many hours or days during migratory journeys, alternating between rapid wing beats and brief hovering periods to feed in flight. This non-stop endurance flight enables them to cover substantial distances of hundreds of miles.
Do they migrate solo or in groups?
Hummingbird moths are primarily solitary migrants that travel alone rather than in coordinated groups or flocks. There are a few reasons why group migration behavior has not evolved in the species:
– Food source – They feed on widely dispersed flower nectar rather than migrating to specific limited food sites which could promote group behavior.
– Navigation – Individuals navigate using independent visual cues like the sun rather than following leaders or social information.
– Lifespan – Their short adult lifespan of a few weeks provides minimal opportunity for complex social behavior to develop between cohorts or generations.
However, loose groupings and aggregations can still form coincidentally if many moths happen to be migrating concurrently between the same start and end points. And some small-scale social interaction may occur around prime feeding sites. But unlike monarch butterflies that migrate in massive congregations, synchronous mass movement in unison is not characteristic of hummingbird moth migration. Their migration strategy essentially involves each individual moth independently making a rapid solo journey.
Do they return to the same summer breeding areas each year?
There is some evidence that individual hummingbird moths may exhibit site fidelity, returning to breed in the same general region each year. However, their migrations do not appear to involve the precise, unwavering return to a specific site like that seen in certain bird species. Rather, they likely navigate back to a more broadly defined area that offers suitable habitat.
This loose site fidelity may arise for several reasons:
– Genetic imprinting – Larvae may imprint on regional environmental cues that help guide adults back to ancestral areas.
– Familiarity – Returning to a known area increases chances of locating food, mates, and egg-laying sites.
– Successful breeding – Prior reproductive success may lead moths to return to where offspring previously thrived.
But the short lifespan, solitary behavior, and diffuse food sources likely preclude precise return to a specific site or coordination between generations. Hummingbird moths lack the cognitive maps, social information exchange, and generational knowledge that enable certain birds to faithfully return to the exact site, tree, or nest each year.
Overall the migration pattern of hummingbird moths is more diffuse, variable, and influenced by environmental conditions between years. But their annual return to favorable northern latitude breeding grounds demonstrates some degree of seasonal site fidelity driven by a combination of imprinting, experience, and evolutionary success.
Do they only migrate once each season?
Most hummingbird moths likely only complete one northbound and one southbound migratory journey per season. However, some individual moths may migrate more than once over a breeding season under certain circumstances. Factors that could lead to multiple seasonal migrations include:
– Unfavorable conditions – A cold snap or lack of food after initial migration may trigger another northward migration.
– Need to breed – Failure to mate or lay eggs may drive a second migration seeking fertile breeding areas.
– Repeat broods – In warm climates with a long season, a second brood may migrate north after the first brood declines.
– Extensive lifespan – Living longer than the typical few weeks could allow additional migration.
– Displacement by weather – Storms may force moths to changed intended destinations.
– Navigation errors – Mistakes in orientation could bring early return migration.
While one migration each way per season is the norm, a minority of resilient individuals may successfully complete two or more migratory cycles in a single breeding season if conditions allow. But for most moths, their short adult phase limits them to a single return north-south migratory journey.
Conclusion
In summary, while not native residents, migratory hummingbird moths are seasonal visitors that make important contributions as pollinators to Ireland’s ecology during their brief summer presence. Careful garden plant choices and management can help attract these fascinating insects and fuel their strenuous migratory journey. Though the concept of such a diminutive creature completing an annual 1,000 mile migration seems unbelievable, it serves as a reminder of the remarkable feats of endurance and navigation performed by even some of nature’s smallest inhabitants. The transient presence of hummingbird moths is one of the many wonders of the natural world on display each summer across Ireland.
