Monday, 9 January 2012

Sparrows should not dance with cranes, their legs are too short.

Today I finally tore myself away from things that I really have to do and went on a twitch. I must admit it wasn't a very long twitch and the object of my ambition is not, or at least would not have been, considered a rarity. However, I had been waiting for more than eight days to see a House Sparrow in my garden and it still hadn't happened this year.

We are into our twelfth year here and for at least the first seven it never occured to me that there would be a time when Sparrows were in short supply here. Of course I knew about the decline in the country, but the flock of up to forty that persistently inhabited the hedge behind our pond was nearly always there. I put up several Sparrow nest boxes but only one got used, but there were a couple of pairs in our roof and at least the same in the cottage below us on Kingsdown Road. Then the decline started here and numbers dwindled. Last year I was still seeing a couple on most days coming to the feeders, but that was all, and then at then end of the year they disappeared completely.

At the junction of Nelson Park Road and Seymour Road, just before you get to the stables, I'd noticed a good flock of Sparrows around the gardens there, when I've been surveying that particular tetrad, so I went over there today. In no time at all I'd found my quarry, a smart male Passer domesticus, in fact I found six. Now that sounds quite good, but it was quite a lot less than I'd seen before and unless the main body of the normal flock was elsewhere then numbers must be down here as well. Strangely I only saw males, I have nothing against a nice cock Sparrow, but unless there are some hens about they won't be around for long.

On the other side of the coin Great Spotted Woodpeckers were fairly infrequent visitors when we first arrived here, but now they are daily guests at the feeders and are drumming out their approval on one of the cut branches of the Ash tree on a regular basis.

I'm not at all sure what had caused the decline in one and the expansion of the other. Much research is being carried out on the predicament that has over taken the Sparrow. One study by Kate Vincent at the De Montfort University has found that in both suburban and that lesser extent rural gardens the annual productivity was lower than in that measured in Oxfordshire farmland. The main cause of this lower productivity was starvation of chicks, usually the first 5-6 days after hatching, during June and July. The results seem to indicate that the chicks are starved due to the lack of suitable invertebrates during this critical period. The full paper of this study was published in Animal Conservation. My own belief is that in addition to the problems they have in rearing young, there is also pressure on surving the winter. In years passed large flocks of sparrows could be found on stubble fields amassing the fat that would fuel them through the winter. Stubble fields are a thing of the past now and highly successful species like the Wood Pigeon are competing against them for what food is available.

Why Great Spotted Woodpeckers are doing so well is another matter, I think they have changed their habits to make more use of garden feeders, but whether this is enough to fuel the increase in numbers that they have had I don't know.


Greater Kent Birder said...

Tony, I know it's no consolation but I've not seen a house sparrow in my garden for years and I can't remeber the last time I saw one in Kingsdown. I've yet to read the paper you cited but the starvation of the chicks is understandable - all the gardens around Kingsdown are clean and tidy (so minimal insects) but thre should be more than enough winter food with all the feeders around.

Derek Faulkner said...

Tony, come to Minster in Sheppey, we have loads of them and I can guarantee that a visit to my garden on any day of the year will see around 30+ Sparrows on the bird tables. I'd happily swap some for the mass of finches that most of you guys seem to get all year round on your bird feeders, I doubt I get any more finches than some people living in the middle of a city.

Susan said...

It's a sad mystery. I read the abstract. We always had reasonable numbers in Rainham - I had the impression it was one of their strongholds in a shrinking distribution though. Plenty here still in central lowland France - and they compete with the swifts for nest space in the building opposite us.

Speaking of cranes - did you see that the Whooping Crane assisted migration program in the US was temporarily halted mid-migration because some dipstick complained that it was a commercial operation and ultralight pilots are not allowed to fly professionally. Fortunately the FAA has granted permission to finish this year's migration, but no one is saying what will happen next year. I assume the FAA is sympathetic though and something will be worked out.