Who Really Killed Cock Robin?
Facts in Chapter 3: The Deepening Disaster
p. 44: The Mayor says, "Mrs. Robin is sitting on her nest so I can't see the babies."
Robins brood both their eggs and young, so the Mayor can't accurately conclude that the eggs have hatched yet.
p. 45: Mayor said Mr. Robin had a new husband to help her raise her brood. But Tony was not so sure. The male had not yet sung, something he must do if he was going to remain, but he Mayor was ignorant of that fact· At 8:00 he heard the new male sing from the hickory tree and ran upstairs to look at Mrs. Robin. She was still broody. Nothing could be hatching under a bird that sat in such a deep trance.
Tony has more information and understanding, but until we can SEE under Mrs. Robin, we have no way of being certain whether the babies have hatched.
p . 49: CR fluffed, fluttered, and shook--symptoms of dying.
Sadly, these are definitely symptoms that many birds show when they are dying.
p. 49: If the fat cells around the nerves were destroyed, he (Rob) would know the bird had died of DDT poisoning.
First: remember that DDT is no longer in use in the US or Canada. If Rob had found that the fat cells around the nerves were destroyed, he would be able to make a reasonable guess that DDT was involved, though there are quite likely other chemicals that cause similar damage. To be certain, he would have also had to analyze the tissues to make certain that DDT was actually in Cock Robin's body.
p. 49: Hard metals like lead, mercury, strontium, and titanium are turning up in the bodies of dead birds and fish.
This was true in the 1970s, and is still true today in some cases.
p. 50: Lead comes from lead pipes in old houses and rain wash from streets, where car exhaust settles. Lead washes into rivers through storm sewers and comes to rest in rivers, pools, and bays.
This is why all new cars manufactured in the US and Canada must run on lead-free gas now, and why new pipes are now made in non-toxic metals or plastics.
p. 50: Mercury gets into plants and animals by way of caustic doda, a mercury-filled product used in industrial centers. Chlorinated hydrocarbons include DDT, DDE, DDD, dieldrin heptachlor---the pesticides.
We now know of many ways that mercury enters the environment, from naturally-occuring mercury in rocks that is released with acid precipitation, mercury from thermometers, fluorescent light fixtures and other home sources, and industrial sources.
p. 52: Bees live only about 30 days and they often die at work.
True.
p. 54: Mrs. Robin has picked up a shell. She is carrying it into my hemlock hedge·and now she is back with a worm·a small, bright green one.
Usually it's difficult to actually see and identify what robins are bringing their hatchlings when the babies are only a day old. This is because robins usually feed nestlings by regurgitation for 2-4 days after the babies hatch.
p. 54: The new Cock Robin came to the nest. He fed a baby! Now Mrs. Robin is stepping down into the nest. She has spread feathers and wings and covered our babies.
Some robin females take the food from the male and feed the babies themselves for the first few days, but individuals vary.
p. 58: The bees were gone. The cloud cover was just enough to put the light threshold so low that the bees could not see well enough to hunt. They vanished, leaving the field to the ants and the players.
True. Bees forage when the sun is high, using its light and warmth.
p. 60: Natural causes for the death of baby robins: crows, bluejays, snakes, and raccoons.
Current research indicates that most nest failures occur at egg rather than nestling stage. Other natural egg and nestling predators include chipmunks and squirrels.
p. 60: Out of two broods of the five eggs that robins generally have, about 3.6 survive.
This must be the result of a specific study, and sounds reasonable. Other studies have found greater or less survivorship.
p. 61: A baby robin died during the night. Mrs. Robin carried it out at five thirty when I was watering my lawn and dropped it near the marsh.
It is very important for the adult to dispose of dead babies so that if the cause of death was illness, there is a smaller chance of other babies being exposed, and so decomposing insects and bacteria don't harm the live nestlings.
p. 61. The Mayor said that mortality is high in young birds.
Mortality in nestling robins is actually lower than mortality as eggs and once the babies fledge. One nestling dying with no clear cause is VERY suspicious.
p. 63: If something was the matter with 3 eggs--they had not hatched--and one nestling was dead, then something was probably wrong with Saddle.
Tony's fear is based on sound reasoning.
p. 64: Saddle's one day old and hasn't made a peep. He should be giving the food call, a loud, noisy squawk. Nestlings scream when their parents come to feed them.
Day-old nestlings aren't nearly as loud as they'll be in a few days, and their call is not a loud, noisy squawk. They only call for food when they feel that their mother or father has lighted on the nest to feed them. But their begging call is important for their parents to hear.
p. 64: I haven't seen Mrs. Robin for hours.
This is a danger sign.
p. 66: It's Mrs. Robin, all right. I found these feathers within her territory. No other female would trespass on her land. Males teach their mates the boundaries of their property, and they stay within them.
Females actually figure out the boundaries of their territory on their own, but it's very true that no other female would trespass on her land.
p. 66: A cat or fox doesn't pluck; they kill and carry.
True.
p. 67: Something was the matter with Mr. Robin. I found her feather out in the watercress. No robin normally goes into an environment like that. Watercress is for herons and wading birds. You may say she was carried there by the hawk, but she wasn't. She was killed where I found the feathers. I could see the impact points where the hawk's wings struck the cress.
Tony is using great observational, reasoning, and ornithological skills to put all this together.
p. 67: Mayor told Tony that the male had not been feeding Saddle. "He's just singing from the hickory and spruce tree. Singing, singing." Tony tells him, "He's trying to attract another female, and if Saddle doesn't give the food call, it's very likely he'll die. The sound is important. The parents must hear this cry. It makes them feed the young."
If the female was sick, she wouldn't be responding to the new male appropriately, and he would naturally sing to attract a new mate. If she was sick, she wasn't tending to her chick properly, and his hunger would make him too weak to make the normal sound. The sound is especially important for a foster male to hear, since his hormones haven't been synchronized with the female's over a courtship and nest-building period. If the baby was too weak to make its normal sounds, the male would indeed just keep singing.
p. 68-69: Tony mentions that the birds must be fed every twenty minutes. Then he made his formula: "When eggs, raw meat, and cereal were wetted down with yeast and water, Tony jiggled his hand above Saddle's head. The tiny bird opened his mouth. Tony dropped a morsel in it, and Saddle swallowed."
This is a reasonable schedule, recipe and technique for giving a baby bird food in an emergency. Nowadays it's actually better to get to a pet store and buy a "hand feeding mixture" which is a powder you can mix with water, which has all the vitamins and the proper balance of nutrition for most nestlings. And nowadays an even better solution is to take the baby bird to a rehab center where the staff will have a much more natural diet and know exactly how often and how much to feed the baby.
p. 70: Tony consults a day-by-day development chart of Song Sparrows from Margaret Morse Nice's Studies in the Life History of the Song Sparrow. His brother had noted that this worked perfectly for robins, too.
Look at Margaret Morse Nice's actual Development Chart (published in 1943).
This really does work for robins except for a few categories. (Unlike song sparrows, robins don't scratch the ground or shell seeds at any age.)
p. 71: Robins depend on their voices to locate friends, establish land borders, and warn of enemies.
This is essential, as Tony knows. This is why it's important that qualified rehabbers raise baby robins whenever humanly possible--they can expose the babies to the proper calls to teach them how to communicate with other robins. But this wasn't possible in Saddle's case.
On day 7: Saddle was still on schedule. He could get off his heels, stand on his toes, and stretch his wings.This information comes directly from the chart that Tony consulted.
p. 72: Saddle's hopping.He's right on schedule.
Again directly from the chart!
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