Hummingbirds that winter in Las Vegas NV – why they choose to stay

                As I cleaned up that backyard just after dawn on the first day of winter, I heard an Anna’s hummingbird scolding me in the tree in the yard to the north of me, while a male Costa’s hummingbird whistled at me from the bottle-brush bush in the yard to the south of me. Both were anxious for me to finish so they could drink sweet water in peace. After the cold night they needed the calories to refuel their bodies.

A female Costa's that chose to winter in Las Vegas.She is sitting on the Texas Sage in my front yard.

Not too far south of Las Vegas NV winter weather is much warmer. Even just 100 miles or so makes a difference of 10 degrees in daytime highs and nighttime lows. In Yuma, 305 miles south of Las Vegas, the December highs are in the high sixties, and lows are in the high forties. So why would any hummingbird choose to stay all winter here in Las Vegas with our normal lows in the mid-thirties and normal highs in the mid-fifties, while extreme lows drop well into the teens?

                When I looked on the Cornell University ornithological site I found that even the experts don’t really know what makes birds decide to go or stay. Since science moves forward by a combination of observation and inference, I will happily go out onto a limb and expound on my observations of bird migration and the inferences I have formed from those observations. Since I spend several days going over the definitions of those two terms with my science students I will refresh your memory on the subject as well.

                Observation is what we can detect with our five senses. If you use the same ‘equipment’ as another person you will observe the same thing. Inference, on the other hand, is an explanation of what we observe. Inference is always open to argument. Scientific law is based on observation; it merely tells you what will happen without any attempt to tell you why. All science theory is based on inference, an attempt to explain how and why things happen in nature. Whenever we venture into the realm of inference we are putting ourselves in danger of being wrong, but that is the price we pay for satisfying our very human desire to know why things happen. It is no accident that a toddler’s favorite word is ‘Why?’

                I lived in Ketchum, Idaho one summer. I spent a great deal of my time walking in the area of the Wood River. During August I watched the young Robins flocking in preparation to leave on migration. The adults were still busy with new fledglings so the older juveniles were on their own to find their way south. They soon left the area while the parents still had adequate food to feed their last charges before they too left for the winter. My inference then was that what drove the migration was the shortening days. Certainly food didn’t enter into the picture.

                I lived in southern Idaho for several decades. There I watched flocks coming and going every spring and fall. Yet we had many year round residents. We would have forty of more robins on every Christmas count. They were living down by the Snake River feeding in the Russian olive trees. Yet these were not the same robins I had watched throughout the valley during the summer months. These Christmas robins were migrants from further north. There was plenty of food to satisfy their winter needs, so why didn’t our summer resident birds stay around and avoid the rigors of migration?

                When you look at the range maps for robins you see that there is an area farther north where they summer and an area farther south where they winter. Between them is a large area where they are year round residents. My inference is that as the northern birds move south the resident summer birds also move further south to leave room for the new comers. So there is a general shift south and then in the spring a general shift north. In this case the migration for those in the middle is based not on length of day or food supply, but on population pressure. One area simply doesn’t have enough food supply to feed that many robins.

                When I lived in southern Idaho I had feeders out for the hummingbirds. Our summer resident hummingbird was the Black-chinned. In the mountains surrounding us, the Calliope hummingbird was also a summer resident. Hummingbirds do not flock to migrate, it’s a solitary activity for them, so I couldn’t watch them prepare to leave they just suddenly were gone.

                For the Black-chinned hummingbird this happened in late July. There was still plenty of food for them, many flowers were at their peak of blossom and small flying insects abounded. But the shortening days announced it was time to go and so they did. The Calliopes would come down from the hills and be on their way as well. In August the Rufus hummingbirds, which nest as far north as Alaska, would come through on their way south to Mexico. I would see the last Rufus on September 15. Unless we had had an unusually early killing frost, there were still plenty of flowers and insects for them to feed on. This was necessary because it takes a lot of energy to migrate. A half-starved bird will die enroute.  They found plenty to eat, but they knew the days were getting short, cold weather was on its way and they had better be getting to their wintering grounds.

                So how does all this apply to our Costa’s and Anna’s? Chances are very good that our wintering Costa’s are not the same individuals that we had in the summer. If you look at the range map, they nest up into southwestern Utah and the Spring Mountains but winter here in Las Vegas. Our summer birds left and then our winter birds came. That would account for the days that I neither heard nor saw a Costa’s at my feeder, while I’ve both seen and heard them every day since.

A juvenile male on the first day of winter. This is probably the same individual who had his early morning picture taken December 17.

Our Anna’s, on the other hand, are probably the same individuals we had in the summer. If you check out their range map, the only place where they don’t live all year round is in the Sierra Nevada Mountains. Those individuals probably move into central California for the winter.

Enjoy our wintering hummingbirds and keep feeding. It’s such a joy to see those energetic birds flitting back and forth here in Las Vegas NV.

Hummingbirds in freezing temperatures in Las Vegas NV – how hummers survive the winter

                The lows were in the mid-twenties here in Las Vegas NV. The highs were in the high thirties, colder than the lows just the day before, when the lows had been in the forties, the highs in the sixties. To think I had complained about the cold then!

                When I went out to check on my hummingbird feeders before dawn, I found they were frozen. The north side feeder was completely frozen; the feeders under the patio roof were partially frozen. I brought them all in to defrost, then refilled them with fresh sweet water. I had them out before the break of dawn, hoping my resident hummers had survived the night. At least half an hour before the sun came over Frenchman’s Mountain, the little Anna’s hummer was chattering away. Soon I spotted her at her favorite feeder. Then I saw the males come into the feeder under the patio roof. All were hungry and glad for the food they needed to recharge their bodies after burning all their stored fuel during the night. Throughout the day I saw and heard hummers around my feeders.

This was taken only a half hour after sunrise. From the size of the bird and the length of tail compared to wing tips I have labeled it an juvenile male Costa's Hummingbird.

This was taken the afternoon of the same day. Looking at the size of the bird, and the longer tail I am calling it a male Anna's Hummingbird.

                I decided my best strategy was to bring the feeders in the house during the night so they wouldn’t freeze. I didn’t want to take them down until the last bird had fed in the evening. I found that wasn’t until almost a half hour after the sun set at 4:26 p.m., meaning I had to wait until almost true darkness settled in to go after the feeders and not disturb the last meal of the day.

                When night time temperatures finally rebounded to above freezing I rejoiced for two reasons. One, I didn’t have to dress so warm to walk the dogs and, two; I didn’t have to bring the hummingbird feeders in every night.

                One friend, who also has her feeder under a patio roof, found her feeder was slush but not frozen, so she simply brought it in to refill in the morning. Saturday morning I got a call. She told me that as she was taking the newly-filled feeder through the sliding-glass door, a hungry hummer hovered right in front of the feeder. She thought he might land on it as she held it, but instead he hovered around as she carried it out to the hook and hung it up. That must have been one really anxious hummingbird.

                I have also managed to attract a great number of other birds to my patio as I have added a thistle-seed sock. Not only do I have my House Finches feeding on it, I have an entire small flock of Lesser Goldfinches coming all day long. When the sack is full, I see as many as 10 finches feeding at the same time. While they are happily eating away on the sock, Mourning Doves, White-crowned Sparrows, House Sparrows and Dark-eyed Juncos eat away at the seed spilled on the patio and grass. In the late afternoon when feeding is at a high I may have eight species coming to my patio, including the two species of hummingbirds that winter over in the Las Vegas area.

The usual one Mourning Dove, a small flock of House Sparrows and a very handsome male House Finch

               

A mixed flock of finches, both House Finches and Lesser Goldfinches feed on the sock.

Notes about the differences in feeding habits of birds: Mourning Doves are strictly ground feeders and don’t much tolerate other Mourning Doves close by, Juncos and White-crowned Sparrows feed exclusively on the ground but are usually in groups. House Sparrows will feed on the sock but usually feed on the ground. House Finches readily feed both places. Lesser Goldfinches never go to the ground. Each has their own niche in the feeding habitat of my back patio here In Las Vegas NV.

Hummingbirds in late fall weather - doing their best to stay fueled

                Hummingbirds that winter over in Las Vegas NV need to keep their energy levels up. During the day it is necessary for them to gain weight in order to survive the cold, long night of winter. In the depth of winter this may mean doubling their morning weight. Yet winter also sees a lessening of flowers and insects that serve to feed the birds, so feeders become even more important to them now than during the warm summer months.

                My feeders get their first customers at dawn and the last ones just before it gets truly dark, long after the sun has officially set. I try not to disturb them at these times, since in the morning they are taking their first high-calorie food of the day and in the evening they are taking their last feeding that will have the get them through the night.

                When we had three days of chilly rain here in Las Vegas my feeders were really hopping. I know for people living in other parts of the country temperatures in the 40s don’t sound so bad, but we’d been having temperatures in the upper 60s in the weeks before. The change was hard on me and the birds both. I handled it by turning on my furnace. The birds handled it by consuming more feed than normal.

Anna's Hummingbird female watching 'her' north side feeder. My neighbors bottle brush is her favorite place to sit and keep an eye out for intruders.

                I watched as my female Anna’s hummingbird came to the north side feeder in the rain. All the while she drank she had to keep ruffling her feathers to shake the rain off. Sometimes she stayed on the perch for awhile just to conserve energy before she took her next drink.

She's trying to keep the rain off. Notice the rain drops on the feeder.

               

Waiting for the sun to come out, early morning after the rain finally stopped.

My patio feeder is under the patio cover, so birds there had the advantage of being out of the rain. Their problem is that it is also where my finch feeder is. Finches use the hummingbird feeders as take off points for getting to the thistle seed sock. At times the arrival of the bigger bird causes the tiny hummer to fly off. At other times they happily coexist on the feeder. The hummer sits there without even noticing the giant on the next perch.

Juvenile male Anna's getting a drink where it's dry. Notice the pink feathers to the right of his eye.

                During the rains only the Anna’s hummingbird came to my feeders. After the rains were over, on November 25, I had my front door open to let in the welcome sunshine and listen to the bird songs. I could hear the whistle of the Costa’s hummingbird. I hadn’t heard that sound for weeks. I thought for sure the Costa’s had left me for the Colorado River, where winter temperatures average about ten degrees warmer than here in Las Vegas. I kept listening, trying to decide if I were mistaken, but no; it was the Costa’s song.

                Then that afternoon I was sitting on my couch talking on the phone, binoculars and camera within reach, when I saw the Costa’s come to the feeder. I grabbed the binoculars and looked to be sure that was what I was seeing. Then I grabbed the camera and with one hand pointed it at the bird, hoping for a usable picture. The lighting wasn’t the best, so I had to use a bright filter to bring out the details, but the picture is proof that my Costa’s is definitely still with me, putting up with the cooler temperatures as we move into winter in Las Vegas.

Proof that my Costa's male is still with me!

November sees winter birds - activity under the hummingbird feeder

                I didn’t have to wait long to find out which birds would come to my yard in Las Vegas NV for wintering feed and when they would come. The first of November I saw a small bird feeding under the thistle seed sack, but when I approached to look, it quickly flew away. However I did get a look at the tail as it flitted over the wall. It had the tell-tale white outer tail feathers of a junco. So I was confident that at least one had come to check out the food supply. I also kept getting glimpses of one lone mourning dove, who would quickly exit the scene as soon as he saw me looking.

My one and only Mourning dove feeding on spilled seeds

                I thought I heard the familiar call of the White-crowned sparrow. I listened but didn’t hear it again. It might have been my old friend the mockingbird mocking me, but I didn’t hear the usual follow up for that. So I couldn’t know if the White-crowns were back or not.

Juvenile White-crowned sparrow associating with a mixed flock of juncos

                Then came November 4, 2013, and all the wintering bird species that I had been on the lookout for descended upon my place, en masse. Not only did they come to feed, they stayed around long enough for me to take pictures of them.

Dark-headed version of the Dark-eyed junco

                I was alerted to the presence by the chittering and chipping that I heard out in the back yard. Dark-eyed juncos, both the dark-headed and gray-headed varieties, were flitting around, talking to each other as they fed on the seeds dropped by the finches. Two finches were on the sock, while another fed on the ground, waiting for his turn on the sock. A single mourning dove serenely walked in the midst of all this hubbub of little birds. One juvenile White-crowned sparrow who was hanging out with the flock of juncos also fed on the ground. Later a solitary House sparrow joined the groups, feeding on the sock and on the ground.

House sparrow males feeds with two house finches on the thistle seed sock

                There was no less activity at the hummingbird feeder. Constantly throughout the day hummingbirds came to drink sweet water. There were female Anna’s, males Anna’s and juvenile Anna’s, then much to my surprise, a mature male Costa’s. The reason the last was a surprise is because I haven’t heard the Costa’s whistle since the first of November so I thought they had left me. No, I could see the very recognizable gorget flaring out to the side as he drank while seated on the perch. The Costa’s is still very much here in Las Vegas, NV.

                The only problem with all this feeding activity is that it makes it hard for me to go out and take care of my plants. I really don’t want to disturb all my visiting birds!