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The house sparrow (Passer domesticus), popularly known as the "sparrow", is one of the most common birds in Germany. But what do sparrow eggs actually look like? Everything about color, size and general appearance can be found here.
In a nutshell
- the typical appearance of the sparrow eggs is a white to greenish ground with dark dots or spots
- each female lays eggs of an individual color and pattern, but which is the same for each egg
- the size of the eggs can vary greatly depending on the weather
shape and color
Sparrow eggs have an elongated oval shape with the typical characteristics known from chicken eggs:
- one pole very flat and almost round
- one pole clearly pointed
The color can vary significantly from animal to animal, but remains largely constant from egg to egg:
- Basic color white to slightly greenish
- rarely greyish basic color
- gray to brown mottling
- Spots partially extremely dense until the basic color is completely covered
The size
The average size of sparrow eggs is 15 x 22 millimeters and weighs around 3 grams. However, this information should be treated with some caution. Because observations show that the size of the eggs can vary greatly. Even within a year, the volume of the eggs in one and the same female can vary by up to 50% in each of the 2 to 3 clutches per season.
Scientists are now of the opinion that they know the reason for this: by adapting the egg size to the weather, the sparrows provide their offspring with the best possible conditions for a start in life. Because while it is generally assumed that a larger egg offers better development opportunities, the state of knowledge for the house sparrow is different. In cold and wet weather, a larger egg provides more reserves of nutrients for better chick development. In warm, dry weather, on the other hand, the oversupply leads to rapid development, which means stress for the organism during development and later in life. Observations show that these animals have fewer offspring and shorter life expectancies.
Notice: This connection may also exist in other bird species, but has so far only been proven for the sparrow through observations and studies.
The clutch
A look into the sparrow's nest usually shows not only one sparrow egg. Instead, the typical appearance of the clutch is defined not only by the actual color but also by the number of eggs it contains. 4 to 6 eggs per clutch are typical, although 3 or even 7 eggs can rarely be laid.
frequently asked Questions
Why are sparrow eggs speckled?The sparrow lays its eggs in open, easily visible nests. The purpose of the dots or spots is to blur the outline of the egg and to best camouflage it against the background of the nest.
Where does the slightly green color of the eggs come from?Egg color is determined by two pigments that are present to a greater or lesser extent in all birds. One pigment has a blue base color, the other a red to brown base color. Depending on the intensity, the ratio of both pigments to each other and the layer of occurrence in the egg shell, the coloring can produce almost any color. In the case of the sparrow, a low occurrence of the blue pigment mixed with minimal influences of the red pigment leads to a slightly greenish coloring.
Where can you find the sparrow eggs?The sparrow is known both as a niche or cave breeder and as a free breeder. This means that nests can be found in tree cavities and nesting boxes, as well as in hedges, forks in branches, and even on ledges on buildings, rocks, etc. This wide spread of the habitats used contributes significantly to its high occurrence.