Atlas das Aves do Arquipélago da Madeira.

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Home METHODOLOGY Systematic Visits

Systematic visits

The systematic visits are based on the calculation of the index of relative abundance of each specie in each grid squares.  All the journeys carried out inside each grid square have come to be registered with GPS. 

The visit to each grid square consists of a correct observation session of the exact duration of 1 hour, controlled through the use of a stopwatch. All the pauses, for example to consult the map, are not counted.  

The speed of progression is controlled appealing to the utilization of a GPS and is situated between the 2.5 km/hour and the 3 km/hour.  The register of the observations is put into effect in units of 10 minutes, which permits for the most abundant species, and is one more tool of comparative analysis of its relative abundance. 

Beyond registering the absolute number of individuals, all the evidences of nesting ground/nesting material/breeding grounds (nuptial stops, transport of food/sustenance, etc.) are also registered.

There are two documentation periods established regarding the official hour of the sunrise and sunset.  In the morning the documentation periods prolong itself for three hours after the first hour after the sunrise (for example  if the official sunrise occurs at 7:00 a.m. then the documentation periods can be effective from 8:00 a.m. on) and in the afternoon will begin up to 4 hours before the hour of sunset. 

Each grid square should be visited one time during the first half of the time period (until May 15) and then again in the second half of the time period (between May 15 and July 15).  It would be good if the second series of visits be made by a certain observer that will, when possible, take advantage of a specific course. 

During the systematic visits, the characteristics of the habitat should be noted (observe the area DOCUMENTS) where one has travelled.  Namely, after every 10 minutes of observation, the observer registers the type of habitat he encounters.

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