Why do Monarchs come to Ellwood Mesa?
Monarchs spend their winter along the coast to escape the freezing inland temperatures. Ellwood Mesa generally has mild temperatures year-round with wind conditions suitable for monarchs, usually under 10 mph. The eucalyptus trees in the Goleta Butterfly Grove create the specific microclimate characteristics that the Monarch butterflies require to survive the winter months. The size and structural diversity of the 75 acres of forest at Ellwood offers an array of conditions for monarchs to choose from. The thick border of outer trees shelters the center trees from wind and storms. Openings in the canopy allow for some sun exposure, but not so much that butterflies get too warm and active. Water is typically available in Devereux Creek and nectar sources include flowering eucalyptus and both native and residential gardens.
When is the best time of year/day to see the monarchs?
The monarchs arrive in the fall and stay until spring – roughly November to February. The population tends to peak near the end of December. The monarchs are most active in February, when they mate before leaving the grove. In the morning and on cool days the monarchs tend to stay in their clusters. In the afternoon and on warm days the monarchs can be seen flying and puddling in and around the grove.
What are the hours you can enter the Grove?
The hours of the Grove are from 8 a.m. to sunset.
Why are some areas of the Grove roped off?
Ellwood Mesa Open Space, including the Goleta Butterfly Grove, is an Environmentally Sensitive Habitat Area (ESHA). To protect the monarchs and their habitat, we ask visitors to stay on designated trails and keep their dogs on a leash.
What does “Enter at your own risk” really mean?
The Butterfly Grove is home to aging Eucalyptus and various trees that are dead or dying and in danger of falling. The paths leading to and through the grove can also be challenging due to walk on especially for those with physical limitations due to the natural and rugged terrain in some areas. The City of Goleta understands that anyone wishing to embark upon these trails and areas does so under their own discretion.
Can people with disabilities manage the paths?
The paths located at the Grove are natural and rough terrain in some areas. This can make it challenging for people with mobility or balance issues.
Do you offer field trips?
In the past our monarch docents led field trips for school and community groups. The program is currently on hold due to safety concerns. We look forward to restarting this program once the butterfly overwintering areas are stable and safe for the public. Updates will be posted on GoletaButterflyGrove.com.
Where do the monarchs come from and where do they go from here?
Monarch butterflies that migrate to the California coast are part of the western monarch population. They come throughout the western United States and the southernmost part of western Canada – west of the Rocky Mountains. In March, after spending the winter here, the monarchs leave these the California coast and start the journey north and outward. The females lay up to 400 eggs on milkweed (Asclepias sp.) plants and those offspring will continue to migrate north. Four to five generations occur over the summer while the monarchs cover the range of milkweed plants up to Canada. Summer monarchs live 4-6 weeks. In fall, the migration begins again. The migrating butterflies live up to 9 months from fall to spring.
A separate population of monarchs spend their spring and summer east of the Rocky Mountains and migrate to overwinter in the mountain forest of central Mexico. Due to the greater numbers of butterflies and longer migration distances, the eastern monarch population is more well-known to the general public.
Why do they aggregate and gather in clusters?
The presence of other monarchs is a cue that a site is suitable. As monarchs arrive, the feedback grows more pronounced and the result can be dense clusters at the scale of tens of thousands of butterflies in a single tree! Monarchs gather together in clusters for protection from wind and storms and to save energy. The cool temperature in the grove helps slow their metabolism, which helps them live longer.
What do they eat and drink?
Monarch caterpillars only eat milkweed (Asclepias sp.) plants, but monarch butterflies can’t eat solid food. Instead of teeth, monarchs have a mouth shaped like a straw (called a proboscis) that they use to drink nectar from flowers and ingest moisture and minerals from muddy puddles.
How long have they been coming here?
Monarchs were first documented overwintering at Ellwood Mesa in the 1920s. The population reached its peak in 1960s and 1970s.
How do they know to come here?
The monarchs that spend their winter at Ellwood Mesa have never been to Goleta. They are five generations removed from last year’s visitors. We don’t know for sure how they find their way – some hypotheses include using the angle of the sun or the earth’s magnetic fields.
Why aren’t there as many as there were in the ‘90s?
The exact reason is unknown. Theories include destruction of overwintering and native milkweed habitat, loss of milkweed (the caterpillar’s only food source) due to drought, and increased predation from small mammals, birds, and wasps.
How long do they live?
Monarchs who migrate to California and spend the winter in groves like Ellwood live up to 9 months from fall to spring. Monarchs that migrate north and east during the breeding season live just two to five weeks as an adult butterfly. There are about 5 generations of monarch butterflies in one year.
How can you tell the difference between male and female monarchs?
Male: the hindwing of the male has thin vein pigmentation with black spots (swollen pouches) along one of the center veins. This is a pheromone sac that helps them attract females. The tip of the abdomen has a pair of claspers.
Female: the hindwing of the female has thick vein pigmentation and lacks the black spots. The tip of the abdomen is rounded with a notch on the underside.
How do you count the monarchs to know how many are here?
Monarch biologists and volunteers visit the monarch sites in the early morning hours while it’s too cold for the butterflies to fly (usually below 13 °C or 55 °F). Using binoculars, they first count the number of butterflies in a small part of a cluster and then extrapolate this count to arrive at a total count for the entire cluster. The average of the total counts of all observers involved in the count is recorded.
The Western Monarch Thanksgiving Count is a volunteer-based programs that collects this count data from hundreds of overwintering sites throughout California and is managed by the Xerces Society for Invertebrate Conservation. For more information or to become a volunteer, visit www.xerces.org.
Why do some butterflies have stickers on them?
White, round stickers with an identification number and a free phone number are placed on the underside of a monarch’s hindwing to provide data on movement between overwintering sites, persistence at individual sites, population estimates, and migration patterns.
Tagged butterflies may arrive in the Grove, but tagging is not allowed on Ellwood Mesa unless permitted by the City of Goleta and other regulatory agencies. If you locate a tagged monarch, please report the details about your sighting to Cal Poly’s Monarch Alert.
Can I touch them?
No, please. Monarchs are very delicate, so we encourage visitors not to handle them. If a monarch lands on you, stay still and enjoy until it flies away on its own.
Can I collect monarchs for educational purposes?
It is unlawful to collect, remove from the wild, and/or captively rear monarchs in California without a Scientific Collecting Permit (SCP) (California Code of Regulations (CCR), Title 14, section 650(a)). Monarchs offer a great opportunity for children and adults to learn about migration and metamorphosis. However, due to recent fluctuations in their overwintering numbers, removing caterpillars from the population could have negative impacts. In addition, captive rearing has been shown to spread disease and affect monarchs’ migratory ability. Rather than collecting wild monarchs or purchasing commercially available caterpillars for use in the classroom, we recommend creating a monarch garden that incorporates flowering plants where students can watch natural processes unfold without bringing the species into captivity. For more information see CA Department of Fish and Wildlife - Monarch Butterfly.
Should I plant milkweed to help the monarch butterflies?
Depending on where you live, maybe. Because milkweeds do not historically occur along the coast, their presence may confuse overwintering monarchs into breeding during the wrong time of the year. Experts recommend that if you live within 5 miles (8 kilometers) of the coast, you should avoid planting milkweed but focus on planting nectar plants for the adult butterflies. Native Ceanothus, Encelia, Eriogonum, Eschscholzia, Hazardia, Helianthus, Horkelia, Isocoma, Lasthenia, and Verbena species, among others, are all good nectar plants. If you live inland, you can plant native milkweed as breeding habitat as well as nectar plants to feed the adult butterflies.
No matter where you live, avoid planting the nonnative tropical milkweed (A. curassavica). Tropical milkweed, which does not die back during the winter, provides year-round habitat for the Ophryocystis elecktroscirrha (OE) parasite that can negatively impact monarch larvae.
For more information see the Santa Barbara Botanic Garden’s Can an Early-blooming Plant Help the Western Monarch?
How can I help the monarchs?
If you want to help early-season monarch populations, you can add flowering plants to your garden but depending on where you live, the recommendations vary. Because milkweeds do not historically occur along the coast, their presence may confuse overwintering monarchs into breeding during the wrong time of the year. Experts recommend that if you live within 5 miles (8 kilometers) of the coast, you should avoid planting milkweed but focus on planting nectar plants for the adult butterflies. Native Ceanothus, Encelia, Eriogonum, Eschscholzia, Hazardia, Helianthus, Horkelia, Isocoma, Lasthenia, and Verbena species, among others, are all good nectar plants. If you live inland, you can plant native milkweed as breeding habitat as well as nectar plants to feed the adult butterflies. No matter where you live, avoid planting the nonnative tropical milkweed (A. curassavica). Tropical milkweed, which does not die back during the winter, provides year-round habitat for the Ophryocystis elecktroscirrha (OE) parasite that can negatively impact monarch larvae. See the Santa Barbara Botanic Garden “Can an Early-blooming Plant Help the Western Monarch?”
It is also helpful to limit pesticide use especially when monarchs are in your area.
You can become a community scientist by volunteering to collect data on monarchs and milkweed. Consider participating in the following community science projects:
Where can I learn more about monarch butterflies and the butterfly migration?
A great resource is the Xerces Society for Invertebrate Conservation. You can also find information through Monarch Joint Venture and Cal Poly: Monarch Alert.
Locally, the Santa Barbara Museum of Natural History and the Santa Barbara Botanic Garden are active in butterfly conservation, research, and education programs.
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