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Archive for May, 2016

           Many birders suffer from the same poor habit that plagued Sherlock Holmes’ companion, Dr. Watson. Sherlock constantly chided him saying “Watson, you look but you do not see.” The same is definitely true of some birders.

            After a new client had visited their lodgings on Baker Street, Holmes would ask Watson what he noticed about the client.   Dr. Watson might reply that the client was middle-aged, slightly shorter than average height with light brown hair. Sherlock, on the other hand, had observed the client more closely and offered a more detailed description.

            He would state, based on the unique tattoo on the client’s left wrist, his rolling gait and his deep tan that he had once been a sailor who spent time in the Caribbean.   Ink stains on his index finger suggest he is now an office clerk and the frays on his collar and sleeves indicate he has limited funds. To compensate for his lack of height, he had extra thick heels and soles on his shoes which were splashed with mud of a specific shade that is only found in one part of Sussex.

            Both men had observed the same client. Watson had looked at him carefully and formed a general impression. Sherlock, on the other hand, saw more deeply. Not only did he form a general impression, he also noticed all the minor details. Same client, two different descriptions. Watson looked, but Holmes saw.

            Similar variations occur when two birders look at a bird. One birder will notice the general impression. The other will see and note all the little details (that at times can help nail an ID). One looks, the other sees.

            For some species a general impression may be all that is needed to identify the bird, a robin, for example.   You have probably looked at thousands of robins. You don’t need binoculars. You can identify a robin easily with barely a glance. But have you ever really observed a robin closely, seen the little details?   Here’s a test: What is the color of a robin’s throat?   Have you ever noticed the small white triangles at the tip of its tail? Does in have an eye ring? Does it have wing bars?   Some birders can’t answer these questions without consulting a field guide or actually looking a robin to confirm the answers.   With common birds it is tempting to just look without really seeing the details.

            A mourning dove is another common bird, often looked at, but usually not seen in detail. Watson could provide the general description of a light brown bird with a long pointed tail and sort legs. Sherlock would have noted its pale blue eye ring and dark cheek spot.   When you spot a flicker, do you consistently look for presence of the mustache that indicates it is a male? Or are you content to simply indentify it as a flicker.

           For common, everyday birds it isn’t necessary to really see the bird in detail. However, for less common birds, it helps to see the details in order to confirm an ID. And for a rarity, it is absolutely essential to observe the bird closely.   Describing a robin as having a dark back and a rusty chest may be adequate for identifying a robin. But if you see an oriole outside its normal range, simply describing it as a black and orange bird is not enough to identify it. You need to see more details.

            Develop the habit of observing all birds closely.   Begin practicing with the common birds. Look closely at every bird. Make it a habit.   Otherwise you won’t remember to see the details when you do find that rarity.

            Henry David Thoreau also noted that not everyone observes carefully. He warned of observational bias where “you only see what you expect to find.” I am guilty of that. Last spring I was casually glancing at my umpteenth Common Grackle of the day when suddenly my companion got excited about a Rusty Blackbird. I wanted to shout “Where? Where?” but realized it was the bird I was just looking at. The fields were overflowing with grackles, so I just assumed this was another one of many. I hadn’t taken the time to notice the shorter tail and overall smaller size.

          I definitely had the tenancy to look at a bird but not see. It was deeply ingrained habit and hard to break. But I finally found the secret technique that worked for me – I would talk to myself. I discovered that verbally describing a bird to myself as I looked at it was a good way to overcome my lazy habit and turn close observation into a routine. And it forced me to take my time and really look closely. As I looked, I would described the bird to myself as a medium size, chunky bird, dark above with white streaked throat, broken white eye-ring, running, not hopping, on a lawn, with long wing projection. If I was birding alone, I talked to myself out loud, voicing the description. I would start by talking about a general impression, then look closely at the head. I would describe the bill, the cap, any stripes and then I would talk about the wings. I talked about every part of the bird. If I was in a group, I had the same conversation, but silently in my mind.   This technique forced me to look at all the details, to really see the bird.   It also helped me remember those details in the event I had to check a field guide later to verify a sighting.

            Don’t fall into Watson’s bad habit of looking but not seeing. Learn to see every time. Start by talking to yourself.  

 

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I once made a list of the most commonly asked bird-related questions I receive. My favorite, although it is not in a top ten FAQ, is “how long do birds live?” It is my favorite because the answer is not a simple number. The answer depends. Moreover, it depends on many different factors. And that gives me the opportunity to explain why it depends.

Living Conditions

One major factor influencing the life expectancy of a bird is its living conditions. A bird living in captivity, say in a zoo or aviary, will outlive the same species living in the wild. In captivity it is safe from predators, sheltered from the environment, receives nutritious food on regular basis without having to hunt for it, and may even receive medical attention when needed. Life in the wild is considerably tougher.

In a similar way, human life expectancy is also highly dependent on living conditions. People living in first world countries tend to outlive those in third world countries, war torn areas or drought regions. They live under better conditions, have better sanitation, access to better nutrition and medical care with fewer mortal perils. So it is not surprising that a captive bird will outlive its wild cousin. A bird that may regularly live for 8 years in the wild, could live an additional 4 or 5 years in captivity. It might be a duller life, but it will be longer. So when we reference life expectancy number, it helps to know if it is based on a wild or captive birds. A bird’s life expectancy also depends on how you define the term. Sadly, most birds do not live to be one year old. The first year is tough on youngsters. Some studies show that the first month may be the most deadly. They are not experienced in finding food or shelter and have not learned to avoid predators. The majority, more than 50% die in infancy or adolescence. If you include all these infant mortalities when calculating the average life span of a species, the resulting number would be depressing low. However, once a bird survives the first year, it can expect a longer life. If you take all the early deaths into consideration you might say the average robin lives less than two year. However, if you only consider those robins that have survive adolescence, they may have a remaining life expectancy of 5-8 years.

A bird’s life span also depends on various factors. Bigger birds tends to live longer than smaller birds. Tropical species survive better than temperate zone species and seabirds survive better than land birds.

Bigger is Better

A typical sparrow-size bird might live 4-6 years. A slightly larger bird, such as a robin, may live an additional 2-3 years.   Crow-size birds live even longer. Hawks, eagles, swans and other large birds may live 20-25 years. Parrots are legendary for outliving their owners. In general, bigger is better.

Old Time Stories

The Guinness Book of Animal Records credits a Siberian white crane as having the longest recorded lifespan at 82 years, although this record is not well documented.

Wisdom

Some long lives are well documented. Albatross are among the largest birds with wingspans of over 11 feet. So it is not surprising that currently the oldest known living bird is a female Laysan Albatross named Wisdom. She is at least 63 years old, maybe older. We can be reasonable certain of her age. Chandler Robbins, a well-known wildlife biologist with the US Geological Survey, banded her on Midway Atoll, a remote island in the Pacific Ocean, in December 1956. Although we are not sure how old she was at that time, it was estimated that she was maybe 4-5 years old. Robbins captured Wisdom again over 40 years later. And other scientists continue to observe her regularly. Her ID band has been replaced five times.

Albatross return annually to their home island to bred, laying a single egg. In Feburary 2014, Wisdom returned again to Midway Atoll at the age of 63. Even more remarkable than her advanced age, she laid and incubated her single egg raising yet another albatross chick. That also ranks her among the oldest mothers in the animal world. Imagine how many children, grand-children, great grand-children, and great-great, grand-children Albatross - Wisdomwould be in Wisdom’s family photograph.

The USGS estimates that in her lifetime Wisdom has flown more than 3 million miles, the equivalent of over 5 round trips to the moon.

Another story that illustrates the longevity of larger birds involves von Humboldt’s parrot. Alexander von Humboldt was a Prussian-born naturalist, explorer and promoter. In the early 1800s he led expeditions to unexplored regions of the Amazon jungle. On one journey he stumbled upon a never-before-seen native tribe, called the Atures, in a remote area of the jungle. The tribe was previously unknown and isolated, not only from the outside world, but even from neighboring tribes. Obviously they had never seen a European before. The tribe had its own unique verbal language, but no written language. Despite the communication difficulties Von Humboldt and the tribal chief hit it off. When it became time for the expedition to move on, the chief gave Von Humboldt his pet parrot which was fluent in the tribal language.

Unfortunately, the explorers may have passed on a fatal disease to the natives and within a few years the entire tribe eventually died off. As a result their unique verbal language was lost to the world. Except for the parrot which, by default, then became the only being in the world to speak their language. After returning to Germany, Von Humboldt, emulating PT Barnum, toured Europe for several years promoting the oddities he discovered on his Amazon expeditions including the only parrot in the world who could speak an extinct language. Audiences were fascinated.

Fred

In the late 1970s Robert Blake starred in popular television detective series called Baretta. His character, Tony Baretta, had a pet sulphur-crested cockatoo named Fred. This species is known for longevity and there are reports on the internet that claim Fred lived to ripe old age of 83. This can’t be verify because in the 1990 Fred was kidnapped (or birdnapped) from the San Diego Wildlife Park where he had been performing.

Maximum vs. Average Lifespan

A long life for one individual does not mean other individuals of that species will live just as long. Recent news reports covered the birthday party for the oldest living man in the US who was turning 105. Yet the average life expectancy of all men is closer to 70 years. Extremes happen but are not representative of the whole.

For example, Stamford University reported on 1746 Purple Finches that were captured, banded and released to the wild and then recaptured again. 1731 of the recaptured finches had initially been banded sometime during the previous 6 years. Only one of the recaptured individuals had been banded over 10 years earlier. So how would you define the life span of these finches? 10 years? Or 6 years?

Large birds do live longer lives. At the opposite extreme are the small birds. Tiny hummingbirds do have a much shorter lifespan than an albatross, but not extremely short. The average hummingbird may live 3-5 years. The record for a ruby-throated hummingbird in the wild is 6 years, 11 months. In its long life this tiny bird weighing less than a dime made 14 migrations trips of 2000 miles or more. The longest lived hummingbird was a larger Broad-tail hummingbird that lived 12 years in the wild.

If someone asks you how long a bird lives, remember the answer is “it depends.” Are they asking about the maximum lifespan, the average lifespan, in captivity or in the wild, big bird or little birds? The answer depends and the factors that impact longevity make interest trivia.

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