Sanctuary for Hummingbirds

If you are a hummingbird, the University of California’s Arboretum provides an excellent home territory. During tomorrow’s Hummingbird Day at the Arb, you can see the hummers enjoying this local sanctuary.

Anna's HB - Female at Grevillea 300 pixels

Anna’s Hummingbird (female) at a Grevillea







Consider the threats to the hummingbird’s life and limb (make that “life and wing”).

Habitat Loss

All of nature’s flora and fauna depend on the surroundings of their native environment. They have evolved to consume familiar food sources and enjoy safe places for shelters and nurseries for their young. Too often, human encroachments have converted such environments through urbanization, agriculture, and logging, leaving the denizens of the wild to retreat into smaller and smaller areas.

The hummingbirds’ challenge in finding an appropriate place to live resembles that of people looking for affordable housing in the San Francisco and Monterey Bay areas.

Long ago, hummingbirds discovered the Arboretum as a fine place to find nourishment and safety, and to raise baby hummingbirds.

They found one significant complication to the sanctuary they discovered: the Arboretum has lots of California native plants that the hummers know best, but this place also grows many plants that thrive in Monterey Bay area’s climate and the Arb’s soil, but are California exotics. The native plants of Australia, New Zealand and South Africa contribute to the Arboretum’s unique collection, which fascinates its many human visitors, but puzzle the hummingbirds.

Happily, hungry hummers have adapted to this special situation: they have grown to love many of the Arboretum’s plants. They show great appreciation for the Australian collection, and have made particular favorites of the Grevilleas and Banksias.

Grevillea 'Robyn Gordon' 300 pixels

Grevillea ‘Robyn Gordon’ – a hummingbird favorite







Pesticide Poisoning

Pesticides provide another important threat to the hummingbirds. Pesticides include synthetic chemicals that kill plants, animals and insects that damage both crops and ornamental plants. Too often, these chemicals unintentionally kill desirable and beneficial flora and fauna, as well. For example, bee colonies have been damaged greatly by exposure to such chemicals.

Hummingbirds, too, are susceptible to chemical poisoning. Their small size and rapid metabolism makes them vulnerable to even small direct exposures to toxic materials.

Pesticides also have indirect impacts on the wellbeing of hummingbirds by killing insects that are an essential source of protein. Hummingbirds are carnivorous, eating insects that they snatch out of the air, pluck from foliage, or glean from spider webs. Hummers could not live on sweet nectar alone.

The Arboretum’s historic avoidance of synthetic pesticides adds substantially to its quality as a hummingbird sanctuary. The Arb’s insects, plants and indeed the soil are naturally clean and safe for hummingbirds.


Feral cats represent a third threat to hummingbirds, as well as to other birds and small mammals. Cats are favored companions for many people, and friendly in their aloof way, but in their wild selves they are fierce predators, with birds as their preferred prey. Unlike other birds, hummers occasionally hover close to a nectar-filled flower cluster. If that cluster is fairly close to the ground, the bird becomes an easy victim of a crouching feline, which could kill a tiny hummer with one swipe.

The Arboretum asks its human visitors to not bring pets with them to view the collections. This ban focuses on dogs and certainly includes cats, although few people take their cats with them for outings. The Arboretum, being a natural environment at heart, is visited occasionally by mountain lions, but those noble creatures are unlikely to feed on hummers, and more likely to discourage visits by feral cats.

Hummingbird Day

Two genera of hummingbirds visit the Arboretum; both are members of the family Trochilidae, which includes a large number of hummingbird genera from the Americas.

The Anna’s Hummingbirds (Calypte anna) are permanent residents of the Pacific Coast, and the Allen’s Hummingbirds (Selasphorus sasin) spend most of the winter months in the mountain forests of Mexico and migrates to northern California during breeding season, from January through March.

Allen's - male HB at rest 72 pixels

Allen’s Hummingbird (male), at rest


Anna's - male HB - at rest 72 pixels

Anna’s Hummingbird (male) at rest








The Arboretum schedules its annual Humming Day to coincide with the combination of breeding season and the arrival of the Allen’s Hummingbird. This is prime viewing time for hummingbird watchers, who can enjoy two eye-catching activities.

First, the Allen’s Hummingbirds tend to be very territorial, so their arrival leads to aerial battles with the resident Anna’s Hummingbirds, who have been simply minding their own business.

Then, for the hummers’ breeding season, the males display unique courtship antics, with amazing steep dives toward a targeted female, culminating in sound effects: male Anna’s make an explosive popping sound; and male Allen’s produce a metallic whine. Later in the season, while the females are feeding their young, there is a good deal of swooping about to collect insects to bring to their nestlings.

As a result of these two activities, during which the hummers ignore their human observers (while staying safe), Hummingbird Day is a great opportunity to see the aerial stunts of these exceptional flyers.

The event, which is each year’s most popular occasion to visit the Arboretum, happens on Saturday, March 4th, and includes guided tours, talks on hummingbird gardening and photography, and special craft activities for children.

Young visitor with a hummingbird toy

Young visitor with a hummingbird toy








Hummingbird Day is one of the Monterey Bay area’s most unusual and most enjoyable encounters with wildlife. Be sure also to browse the plant collections during your visit.


What: The annual celebration of hummingbirds. Walking tours, talks, and children’s activities with a hummingbird theme.

When: 10:00 a.m. to 4:00 p.m., Saturday, March 4th

Where: UC Santa Cruz Arboretum, on Arboretum Road, west of Western Drive

Cost: $10 for public; $5 for members of the Arboretum; free for UCSC students and children under 12

Parking: Free

Information: Visit the Arboretum’s website.

Tour Offers Insights to Growing Citrus

The Monterey Bay chapter of the California Rare Fruit Growers recently organized a members-only tour of a local citrus nursery’s growing grounds, in Watsonville.

Aaron Dillon, our tour guide, shared the history of Four Winds Growers, which was started by his great grandparents. He described the current operations and the pests and diseases that are challenging the entire citrus business.

10-17-14 Aaron Dillon

One threat to citrus trees is the citrus leafminer (Phyllocnistis citrella), a very small Asian moth that lays its eggs in the tissue of citrus leaves. The eggs hatch into larva that feeds on the leaf, leaving a clearly visible, serpentine trail just below the surface of the leaf. Leafminers disfigure the leaves but rarely cause serious damage.

A greater threat is the Huanglongbing disease (HLB), which is known by the common names “citrus greening disease” and “yellow shoot disease.” HLB kills citrus trees.

A tiny insect, the Asian citrus psyllid, transfers this disease from tree to tree as it feeds. Because there is no cure for HLB, the control strategy is to find and stop the insect from spreading the disease. This pest has greatly reduced southern California’s citrus nursery industry, and has very recently been spotted in the San Jose area.

The citrus industry has developed regulations and procedures for propagating citrus trees in greenhouses, while keeping Asian citrus psyllids outside. The tour group entered an enormous greenhouse through an antechamber, in which a large fan produced positive air pressure to exclude any psyllids. The outer door closed, the fan was turned off, and an inner door opened to allow the group to enter the working area of the greenhouse.

Inside, a greenhouse worker, Alicia, expertly demonstrated the process of grafting a citrus scion to a robust rootstock. A skilled worker can graft 1,000 plants in a single day.

10-17-14 Grafting Orange Scions

Aaron Dillon engaged the interested visitors with a wide-ranging presentation of many aspects of growing citrus trees. He demonstrated the extensive facilities in a large greenhouse where roses had been grown previously, and proudly showed an even larger new greenhouse now being readied for an expansion of propagation activities.

10-17-14 Visitors in the Mist

Four Winds Growers propagates popular varieties of orange, mandarin, lemon, lime, grapefruit, and kumquat. For details, visit the nursery’s website <> and click on “Our Citrus Trees.” Dillon listed three interesting varieties that consumers will enjoy in the future:

  • Vaniglia Sanguigno (acidless sweet orange)
  • Lee x Nova Mandarin (88-2 mandarin hybrid)
  • New Zealand Lemonade (sweet lemon hybrid)

For information on these and many other varieties, browse to the amazing Citrus Variety Collection website, maintained by the University of California, Riverside <>.

Many varieties of citrus trees grow well in the Monterey Bay area, and local nurseries have many choices in stock currently. Growing information is readily available on the websites of the California Rare Fruit Growers <> and Four Winds Growers. Pest control advice for home gardeners is offered by the Citrus Pest & Disease Prevention Program