Actually, it’s not really my milkshake, and, technically, it’s not even a milkshake at all — it’s a basic solution of sugar and water, boiled and then cooled to room temperature, that the local hummingbirds seem to find irresistible.

After a short trial period, my husband hit on just the right recipe to keep the tiny birds coming back for more.

Almost a year ago, after years of talking about it, we finally bought a hummingbird feeder. It’s proven to be a good investment — we paid $6.99 for it at Ace Hardware and got a $5 rebate. After my husband hung it under one of the second-floor eaves of the 100-year-old house we live in, it only took about 24 hours for the hummingbirds to home in on it.

At first the birds came and went freely, flitting and zooming to and fro outside our back door as we had hoped. We watched them with delight and curiosity, grateful to have a chance to observe the fast-flying feathered creatures as they slowed down momentarily to perch on the feeder. My husband hung a pair of binoculars by the back door so that when the hummingbirds came to take a drink we would be ready for a close-up. With the aid of magnification, I could make out the markings and movements of their minute bodies as they sipped the offered elixir. Fleeting glimpses as they were, my first few observations through the binoculars quickened my heartbeat and gave me a little thrill. We had lured the hummingbirds to our backyard, and there they were, unwittingly participating in our surveillance. But, really, the idea was to give the energy-burning pollinators and voracious insectivores a place to drink and rest. And then spy on them in the process.

Within the first week we learned that our urban Golden Hill neighborhood provides habitat for many a hummingbird species. Prior to putting up the feeder, we had rarely seen the birds in our backyard, and we were always pleased when one would make an occasional visit. After a few weeks, we got accustomed to seeing several every day. With the aid of the Smithsonian encyclopedia Birds of North America, we identified our feeder’s most frequent visitor to be Anna’s hummingbird, which also happens to be the most common species of hummingbird found in San Diego County. The males are easy to spot, with iridescent red throats and crown feathers that reflect light, while the females have green bodies with light gray-brown underbellies and a tiny patch of iridescence at the throat.

The first time I saw another species in our backyard, I thought I was imagining things. Instead of the usual flash of Anna’s ruby red, I thought I caught a very brief glint of shiny copperish gold. It was a Sunday morning, and we were just finishing breakfast at the table, from where we have a view of the feeder.

“What was that?” I exclaimed, knowing my eyesight isn’t the greatest and I could have mistaken an unusually bright Anna’s hummingbird for an unfamiliar species.

“I saw a flash of gold!” my husband said, getting up to look out the window in case the bird came back. I told him that’s what I thought I saw, too, and we agreed that it was probably a species that we had not previously observed in the environs of our feeder.

As it turned out, a Rufous hummingbird had found our feeder en route south from his more northern territories, which range from Oregon to Southern Alaska. He must’ve been visiting San Diego on his “neotropical migration,” as noted in Birds of North America. We knew it was him when we read in our book that Rufous’s throat flashes golden brown in the sunlight. Rufous hummingbirds aren’t known to hang around long in this town, but they are known for being able to locate feeders they haven’t visited for months. We spotted him only a few times in the summer, accompanied by a distinct whirring of wings, and we’re awaiting his return.

In the meantime, other avian visitors have kept us occupied. Only a few days after the birds had established a somewhat predictable pattern of drinking throughout the day, a dominant male Anna’s laid claim to the feeder. He made it his business to buzz away other males of his species and would tolerate only a few females. He developed several lookout points around the yard, his favorite of which is still on the cable wire that cuts across our second-floor porch. He tucks himself right under the eave of the house on the end of the wire, about two feet away from the feeder, hidden from direct view but close enough to discourage any other birds from taking a drink. Just as the thirsty creatures come in for a landing, he bursts forth from his post to chase them away. On his victory lap back to the wire, he stops to perch on the pomegranate tree that grows between our house and the neighbor’s. There he lets out a long series of clicks and twitters, a song that we’ve learned to interpret as “Y’all better watch out; this is my turf!”

Though it was kind of comical to see such a dainty animal behaving aggressively, we knew the male’s dominance had to be curtailed. The other birds were wasting precious energy trying to get a share of the tasty “milkshake,” defeating the purpose of having the feeder in the first place. So it was my husband, a former U.S. Marine and a combat veteran, versus a four-inch, four-ounce flying organism. It was time to show that hummingbird who was boss.

Initially it was enough for my husband to guard the backyard territory, shooing the possessive “humming-bully” when it got close to the feeder. For a while it worked, and even my husband’s or my presence in the doorway would discourage the bully, the same way a stern teacher’s pointed stare can nip impish behavior in the bud. But soon the determined bird found that he could simply sit just out of harm’s way, on a nearby tree, and swoop in when my husband turned his back.

This called for more drastic measures. One morning, I was happily scrubbing the sink when I heard a commotion and saw movement outside the frosted-glass bathroom window. I ran out to see what was happening and found my husband on the back porch waving the broom and shouting up into the trees. Apparently the male hummingbird was no longer daunted by the mere presence of a human, and it had become necessary to enlist reinforcements. Laughing and wielding the broom, my husband explained that the tiny bird had buzzed him, warning him to stay away, while he was sweeping the porch in the vicinity of the feeder. As if he was competition.

That bold move put the tough little hummingbird on the punk list. The next step was to restrict his access to the feeder by wrapping a cloth around the perches, taking it off in the evening when he was tired and less vigilant. Before sundown, the other birds would come along and get their fill to keep warm for the night. But one day, in broad daylight, when the cloth was in position and the feeder was closed for business, the feisty male found an opportunity to reestablish his dominance. He swooped in close to the feeder, darting between the folds of the rag methodically, looking for a way in. Eventually he discovered the “holes” in our plan, literally, feeding himself right through the tiny tears in the old T-shirt we were using as a barrier.

We were pretty amazed at the little animal’s fortitude, and of course we respected the fact that he was running himself ragged trying to keep the other hummingbirds out of his territory. He even began courting the “humming-babes” right out there on our back porch! During courtship, the male Anna’s hummingbird performs a high-speed air dive, ending in a distinctively loud “chirp” that comes from the bird breaking the sound barrier at the bottom of the swoop. Our resident male has taken to diving right outside our door, and we hear a series of horny “chirps” every day. If we’re lucky, we can catch him in the act, ascending to heights up to 130 feet and then zooming headfirst towards the porch in a crazy dive-bomb plunge, only to veer off at the last millisecond and head back up in the air to do it again. The maneuver is estimated to put more than 9 Gs of force on the hummingbird’s body, a force that my husband informed me would cause even the most advanced fighter aircraft to break apart. That stunt certainly requires a lot of energy.

With cold winter nights coming, and the prospect of a young brood of hummingbirds living nearby in the spring, we knew we had to do something to ensure reliable “milkshake” access for the hummingbirds that share our yard. So a couple of months ago, in early winter, we finally had to buy another feeder. It wasn’t as thrifty a deal as the first — we paid $10.99 for it at Home Depot and didn’t get a rebate — but it has proven to be an equally sound investment. The dominant male still does his thing out there, but now the other birds pretty much ignore him and take their drinks from whichever feeder he isn’t guarding at the time. We’ve even seen three hummingbirds peacefully sipping all at once on the new feeder!

There are still a few tussles between males, which involve two birds spiraling speedily around each other, red feathers flashing, until one gets too close to the ground and has to fly off in retreat. We had no idea hummingbirds were so scrappy!

Despite the competition for females and food sources, the addition of the second feeder has given the dominant male hummingbird more time to focus on finding a mate and has given the other hummingbirds a chance to hang around the yard a bit more. Maybe we’ll catch another glimpse of the blue-throated hummingbird my husband was lucky enough to see once, perhaps drawn north to California from its normal mid-coastal western Mexico range by warming temperatures. Hopefully our San Diego backyard will continue to be inviting to many a hummingbird, a species unique to the American continent and thus on par in importance with its larger and more well-known avian cousins, the wild turkey and the bald eagle. We’ll be looking out for the little ones.