I got an email the other day, from a reader who carried out interesting experiments with his bird table.
He filled a standard, nine-inch feeder with sunflower seeds and was surprised to find it empty a couple of hours later, despite the fact there didn’t seem to be many birds around at the time. So, he filled it again and sat down to watch closely.
Within two hours, what he describes as "a family of four coal tits" emptied the feeder again. Before he refilled the feeder, for a third time, he counted the seeds. It held 3,600.
Simple arithmetic shows that each individual bird was accounting for 1,800 sunflower seeds, or 600 an hour, which is one every six seconds (I think it is, anyway — I was never very good at sums). The last words in the email are: "Isn’t that some appetite for a tiny little bird?"
It certainly is. In fact, I reckon it’s impossible. These sunflower seeds have two kernels in a hard outer shell. Each bird would have to extract a seed from the feeder, fly off with it, crack it, swallow two kernels and fly back for the next one, all in six seconds. And they are small birds, so their crops would only be able to hold a dozen or so kernels at any one time.
I used the internet to try and solve the mystery. Eventually, I found what I was looking for on an English website devoted to garden birds.
It said that coal tits occasionally store food in times of plenty, and use the store when times get harder.
This is interesting. I know that some bird species do this, but I didn’t know coal tits were among them. It’s common among members of the extended crow family. Jays, which are crows, regularly bury caches of nuts, seeds, and acorns in leaf litter on the woodland floor. Sometimes, the caches are not used, for one reason or another, and the seeds or nuts germinate. So jays are reckoned to play a significant role in woodland regeneration.
In recent years, there has been an increasing focus on quantifying the intelligence of various bird species and families.
The crow family is reckoned to contain some of the most intelligent birds in the world, and their habit of caching food supplies is an aspect of their behaviour that scientists use as a yardstick to measure intelligence.
Hiding food supplies when they’re plentiful, and retrieving them when they’re scarce, requires memory and a degree of forward planning. This is not the sort of thing associated with the typical 20th century notion of ‘bird-brained’ creatures that are just a bundle of instincts responding to stimuli in the here and now. Coal tits may be more intelligent than we realised.
Something else to look out for at your bird table, particularly if you live in the east of the country, is greater-spotted woodpeckers. They became extinct in Ireland several hundred years ago, but seem to have re-established themselves in the last couple of years, with multiple sightings in Cos Wicklow, Louth, Kildare, Meath, Down and Antrim.
They quite regularly visit peanut feeders, and, this year, some woodpeckers visiting bird tables in Co Wicklow have been juveniles, an indication that they have probably bred successfully in the county.
Adult, greater-spotted woodpeckers have a small, red spot on the back of the neck, but in juveniles the entire crown is bright red. So keep your eyes open, and, if you do see one, whether it’s an adult or a juvenile, make sure to inform BirdWatch Ireland. In the meantime, I’ll keep you updated on this rather exciting piece of breaking news in the world of Irish garden birds.
dick.warner@examiner.ie
a d v e r t i s e m e n t
This appeared in the printed version of the Irish Examiner Monday, December 01, 2008
