Marked Birds Database concept – the basics

Before you start working with the Marked Birds Database, it is good to know how it works and how it is set up.

In this article I will briefly explain the basic concept.

See this explained in this short video:

Note: the video shows a relatively old version of the database; however, the principle is the same.

How it works

Central to the Marked Birds Database are birds.

To each bird you can add:

  • One or multiple Markers:
    • Leg ring
    • Collar ring
    • Wing tag
    • Nasal saddle
  • Ringing details for each Marker
  • Observations of different types:
    • Personal observation
    • Observation by 3rd-party
    • Bird not observed
    • Camera trap
    • Capture – ringing
    • Capture – control
  • Unlimited number of images to each observation
  • Life histories in multiple formats:
    • Plain text
    • PDF
    • Image
    • Any file format
    • Web link

Markers and Marker Events

Each Marker is added individually and has at least one and sometimes multiple Marker Events. Several types of Marker Events exist:

  • Marker fitted
  • Marker observed damaged
  • Marker color changed
  • Marker observed lost
  • Marker re-fitted
  • Marker replaced

When adding a bird with Markers, a Marker Event is created for it of type ‘Marker fitted’. Should you at some point observe the bird and see that one of the Markers is missing, you can create a new Marker Event for that Marker of type ‘Marker observed lost’, and so on.

This creates  a ‘life history’ of each Marker.

Current Markers

As you can see from the types of Marker Events, Markers can be lost or replaced. When this is the case, that particular Marker is not fitted to the bird anymore.

You can indicate whether a Marker is fitted or not by setting its status ‘Current Marker’ to Yes or No.

Current Marker Codes

After adding a bird with Markers to the database you need to be able to find it again.

This is done by assigning a ‘Current Marker Code’ to the bird. This code is a representation of the bird in the system, and typically describes the current Markers that the bird is fitted with.

For example: a bird that is fitted with a single metal ring ‘Arnhem 1.234.567’ will be represented in the database by the Current Marker Code: M[Arnhem 1234567], or if you want to use a different notation method: M-Arnhem 1234567.

When a bird is fitted with a color ring, that ring is typically used to refer to it. So the Current Marker Code for a bird that is fitted with a metal ring as well as a red ring with code ‘ABC’ will typically be R[ABC] or R-ABC.

Current Marker Codes are typically automatically generated and displayed in a notation of your choice. To make searching easier, characters in the code such as dots and hyphens are removed.

Visual Displays

For birds that are fitted with one or more leg rings, the way the rings are fitted is shown by using a ‘Visual Display’. This shows you on which leg the ring was fitted, what the color of it was and which code was on it, including the reading direction.

A summary of the ringing details is displayed below it. Note that Visual Displays can only show Markers that are currently fitted to the bird.


For those projects for which no Visual Display exists, the Markers are shown in ‘List view’. This shows Markers that are currently fitted and that are not currently fitted.


The code in front of each Marker indicates the type:

  • CC = color coded
  • CU = color uncoded
  • MT = metal
  • AL = aluminum
  • FC = flagring coded
  • FU = flagring uncoded


A bird fitted with a metal ring and a color ring Green Y.BSB. The Current Marker Code is ‘G-YBSB’.

Three observations have been logged (one for the ringing session and two field observations) and a total of 6 images have been added. (Click for a larger view.)



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