Bird's detectability and number of visits to the area
Abstract
Bird counting methods usually are based on 1-3 visits. As a rule strong bias of results were indicated (Verner 1985). This bias is not very important if one is interested in counts of a single species. The problem arises when one is interested in communities of birds. If different species show different patterns of activity then the ability of an observer to detect those species must differ. Thus, a small number of visits will lead to over estimations of the number of some species and under estimation of other species. In this paper we investigate the influence of detectability on the optimal number of visit. We developed a simulation model of transect counts and used data collected during two years of transect study on avifauna of the Bieszczady National Park as an imput data for the simulations. Then we compare the simulation outcomes with the field data.
© PRUNELLA Publishers
All rights reserved. No part of this publication may be reproduced, stored in retrieval system or transmitted in any form or by any means, photocopying, elctronic, recording, etc. without the prior written permission of the publisher, PRUNELLA Publishers - RNDr. Marián Janiga, CSc., Vavra Šrobára 1524/6, 03401 Ružomberok, Slovakia, IČO: 30 525 764. Permission requests for creating new collective works, for resale, for advertising or promotional purposes, or for general distribution, should be addressed to the publisher as mentioned in the Slovak Copyright Law. Free submission of an article for publication entails the author(s) irrevocable authorization of the publisher to collect any sums or considerations for copying or reproduction payable by third parties, as mentioned in the Slovak Copyright Law. EV 3492/09.
