The accuracy of the territory-mapping technique for estimating the abundance of densely breeding Hawfinches was tested in an old and unfragmented lime-oak-hornbeam forest in the Białowieża National Park, E Poland. Hawfinch numbers estimated from counts of the whole bird community carried out with the application of the standards of the improved mapping technique were compared with seven-year data on the bird's true numbers, which are known from parallel intensive nest searches and persistent tracking of the movements of pairs. In a forest with a dense population of Hawfinches the mapping technique underestimated their numbers by 20% in years of moderate density and by 35% during high-density years. Even though the underestimation was negatively correlated with the true density of Hawfinches, the figures obtained by both methods reflected year-to-year changes in a similar way. An improvement in mapping data is achievable either by closer attention being paid to the species during standard visits (the best ones for surveying it), or post factum by the introduction of a correction factor into the mapping-technique figures.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 39 • No. 1