Colony Loss surveys are filed all around the world and New Zealand beekeepers are global leaders in their participation rates. COLOSS director Pike Stahlmann-Brown, of Landcare Research, is keen to keep it that way and so explains the validity of the data collected and that Kiwi beekeepers who haven’t yet completed this year’s survey have a few weeks remaining to do so.
Colony loss surveys are now regularly conducted in more than 40 countries worldwide. An analysis soon to be published in the Journal of Apicultural Research reports on losses for 36,000 beekeepers with 1.3 million colonies in 37 countries. Excluding New Zealand, the average national over-winter loss during winter 2021 in the Southern Hemisphere / winter 2021-22 in the Northern Hemisphere was 21.6%. Our over-winter losses during this time were 11.3% (they have since risen to 13.5%).
The New Zealand Colony Loss Survey is now in its ninth year. Our survey regularly has the highest participation rates in the world, both in terms of the share of all beekeepers who complete the survey and the share of registered colonies covered in the reporting. Such high participation underscores the integrity and reliability of the data.
Still, about once a week, I have a conversation with a survey skeptic. Most often, the skeptic says something along the lines of “I don’t believe the survey results because beekeepers who had high losses don’t answer the survey or don’t answer truthfully”. That is, they think that actual losses are way higher than people report.
I recently attended the biennial conference of COLOSS, the international collective of researchers who pioneered the science used in COLony LOSS surveys. It was held in Slovenia (formally called “Carniola”, a term that will no doubt be familiar to many readers!). An interesting presentation by Jiří Danihlík from Czechia addressed the issues raised by survey skeptics head on. Czech beekeepers register their apiaries and colonies with the Ministry of Agriculture each September. In January and February, the State Veterinary Administration samples registered colonies in each of the country’s 76 districts. At the same time, Jiří conducts the Czech Colony Loss Survey. Thus, Jiří was able to compare colony losses reported in the survey with colony losses recorded by the State Veterinary Authority for the same period of time!
And what did he find? Losses reported in the colony loss survey were within 10% of losses recorded by the State Veterinary Authority in 68% of Czech districts. So, if beekeepers in a district reported 10% losses, official statistics showed losses of between 9% and 11% seven out of ten times. What’s more, where losses reported in the survey differed from official data, losses reported in surveys tended to be higher.
Czech beekeepers differ from New Zealand beekeepers in many respects. For one, 60,000 beekeepers in Czechia look after about the same number of colonies that 10,000 beekeepers manage here. But are New Zealand beekeepers systematically less honest than Czech beekeepers? I wouldn’t bet on it.
If you haven’t completed your 2023 survey yet, please check your inbox for a reminder that was sent on 1 November 2023. If can’t find the email, or if you didn’t receive a link, send your apiary registration number to brownp@landcareresearch.co.nz, and I’ll re-send your link.
Commenti