If a bird egg lies on the ground outside of the nest, many walkers feel sorry for it. If it is a blue egg, there is also the question of which parent bird it belongs to.
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Blue Bird Eggs
It has not yet been clearly clarified why some bird species lay green or blue eggs. However, there are various theories about this. Researchers at City University and Lancaster College assume that the color of the eggshell has something to do with temperature. Because the blue shell ensures that the inside of the egg does not heat up too much. It acts as a kind of sun protection and creates bearable temperatures for the growing chicks.
Another theory sees the blue shell as a kind of quality feature that is used to encourage males to take care of the brood in certain species. Because the color intensity of some bird species, such as the pied flycatcher, indicates the physical condition of the mother bird. The following applies: the more intense the blue, the healthier the mother is and the more worthwhile it is to care for the offspring. On the other hand, if the bird’s eggs are only pale blue, this means that weak chicks will be born. In this case, brood care is not worthwhile from the male’s perspective.
Bird species from G to R
The cuckoo (Cuculus canorus) is a special case because the females can adapt the eggs to those of the host bird species. One of his favorite species, in the nests of which he lays a blue cuckoo egg, is the redstart.
Gartenrotschwanz (Phoenicurus phoenicurus)
- Colour: greenish-blue, matt to glossy black
- Markings: reddish-brown spots on the stump (rare)
- Breeding season: late April/early May to late July
- Habitat: Light and dry deciduous forests, edges of forests, parks with sparse tree population, edges of villages, orchards, industrial plants, also mixed and coniferous forests if there are large populations
Bullfinch (Scientific name Pyrrhula pyrrhula)
- Colour: light blue to bluish green, cloudy bluish
- Markings: deep purple-brown to almost black spots sparingly towards the blunt pole
- Breeding season: April to August
- Habitat: Coniferous forests, light mixed forests, parks or gardens with spruces
Heckenbraunelle (Prunella modularis)
- Colour: green-blue
- Drawing: none
- Breeding season: April to July (two broods)
- Habitat: Coniferous forests, light mixed forests, parks or gardens with spruces
Robin (subspecies: Erithacus rubecula superbus)
- Colour: bluish green
- Markings: rust-brown or rust-reddish spotted or clouded; reinforced in the direction of the blunt pole (rim formation possible)
- Breeding season: mid-March to August
- Habitat: Deciduous, mixed and coniferous forests, alluvial forests, bushes, hedges and areas close to water
Bird species from S to T
Singdrossel (Turdus philomelos)
- Colour: sky blue
- Drawing: none
- Breeding season: April to July (two broods)
- Habitat: deciduous, mixed and coniferous forests, alluvial forests, moor forests
Star (Sturnus vulgaris)
- Colour: light blue to light green
- Drawing: none
- Breeding season: mid-April to mid-May
- Habitat: widespread with the exception of closed forest areas
Pied flycatcher (Ficedula hypoleuca)
- Colour: (bright) blue
- Drawing: none
- Breeding season: May to July
- Habitat: Deciduous and mixed forests, parks, gardens
Measures to be taken if bird eggs are found
Because birds build their nests securely, eggs usually don’t fall out accidentally. However, there is a possibility that the parents will deliberately throw an egg out of the nest or the brood cavity, since a weak chick will grow up in it, whose chances of (survival) life are slim. If you want to save this life, then you should not touch the bird’s egg with your bare fingers and hand it in immediately to a body that is familiar with bird’s eggs. Incubation in your own four walls is not recommended because it is a complex process. In addition, rearing the chicks appropriately at home is extremely difficult.