The participatory campaign “Hour of the Garden Birds” has something good to report this year, but also a sad one: more than 140,000 nature lovers took part in the bird counting campaign at home. The focus was particularly on the concern for the sick blue tits. The preliminary evaluations show that around 300,000 blue tit birds (Cyanistes caeruleus, a small passerine bird in the tit family Paridae) have probably fallen victim to the bacterial plague. The German Nature Conservation Union (NABU) is now hoping for lively participation in the next hands-on campaign: insect counting is the order of the day from May 29th.
Around twice as many participants as in the previous year – NABU is enthusiastic about the success of the “Hour of the Garden Birds” 2020. Apparently, many people used the increased stay at home due to the Corona crisis to take a closer look at their feathered visitors. Some may also have been motivated by reports that blue tits are currently experiencing a similar situation as we are: they are being afflicted with an infectious disease that leads to pneumonia. Apparently, no virus is the cause in this case – the bacterium Suttonella ornithocola has now been identified as the pathogen.
Number of victims of a bacterial pandemic
This germ, which is harmless to humans, was initially only known from Great Britain, but did not cause a nationwide mass death there. In Germany, Suttonella ornithocola was then detected for the first time in April 2018. “The massive, supra-regional occurrence this year is new for this pathogen. In addition to Germany, at least Luxembourg and Belgium are also affected,” says NABU Federal Managing Director Leif Miller. It is now becoming apparent how many blue tits have actually fallen victim to the pathogen in Germany.
“Nationwide, 22 percent fewer blue tits per garden have been reported,” reports NABU bird protection expert Lars Lachmann. These are by far the lowest population numbers since counts began in 2005. To find out whether the decline is really due to the epidemic, the conservationists compared the changes in blue tit numbers for each county with previously recorded data. Concerned bird lovers had reported sick or dead blue tits to NABU. “The more reports of dead tits we received from a district, the greater the population decline there,” says Lachmann.
As he and his colleagues estimate, against the background of the total population of around 7.9 million adult blue tits in Germany, around 300,000 birds died from the disease. Fortunately, the situation now seems to be improving: the bird epidemic, which has so far been unique in Germany, has been declining significantly since the end of April.
Winner and Loser
In addition to the problem child, the blue tit, the hands-on campaign was of course also about the population development of all other birds. This year, the participants in the campaign discovered an average of just under 31 individual birds from a good eleven different species within an hour, reports NABU. Once again, the house sparrow is at the top of the list of bird sightings with 5.3 specimens per garden. In the early years of the campaign, the blackbird outperformed the sparrow three times. But this has not happened in recent years, because these popular songbirds have also suffered from a pathogen: the Usutu virus is still polluting blackbird populations. However, with an average of 2.91 specimens per garden, this species was able to match the result of the previous year and was sighted in 94 percent of all gardens within an hour.
In addition to the losses in the blue tit, there have also been drops in the starling and the greenfinch, reports NABU. Even with the little wren, the numbers are constantly falling from year to year. Fortunately, there were no further declines in the case of the problem children, house martin and common swift. But these once-common urban birds remain far from their previous population numbers, experts say. Apparently there were also winners: the populations of the wood pigeon and collared pigeon in particular have increased, and the jay and great spotted woodpecker were also able to set new records in population density.
The detailed results are available at www.stundendergartenvoegel.de .
Counting insects will soon be the order of the day again
If you enjoyed the hands-on campaign, you can now add more dates to your calendar: From May 29th to June 7th, NABU is once again calling on nature lovers to get involved: the Citizen Science campaign “Insect Summer” is coming up. Within an hour, the insects in the home environment should be recorded again. This year the focus is on six-legged celebrities: the ladybugs, of which there are 70 different species in Germany. However, an “alien” has been mingling with them for several years: the counting campaign is intended to show how far the Asian ladybug has spread, along with further information about the insect world. Further information on the project can be found at www.insektensommer.de .
Source: NABU