Freitag, 19. April 2013

Portrait (April 19th, 2013) - Corvus corone LINNAEUS

In the most cases, I'm not able to make articles about birds because I don't have the right equipment to make some good photos. However, some birds are accustomed to humans and not so shy. Last Week, I met such a bird, which was very curious and not afraid to get in contact with me. This bird was Corvus corone corone L. from the Corividae family (Corvids). In English, the species is known as Carrion Crow and in German as “Rabenkrähe” or “Aaskrähe”. 

C. corone corone - habitus (note the feathers on the beak)
The Carrion Crow is a larger bird, which can reach an average length of 47 centimetres (18.5 inches) and an average weight of 540 grams (1.2 pounds). The beak is thick and completely black. There are also some feathers at its base. It's mostly straight but curved sharply at the top. Compared to other crows and ravens, the head is very flat. The voice is a bright “kraah” or “aark”.

C. corone corone - minutes before; the bird checked me
with caution before it aproach

The plumage has a shiny, black colour (typical “Raven black”) with a slight blue tint and the wingspan is between 85 and 110 centimetres (33.5 to 42.3 inches), while the Rectrices (the “tail feathers”) are narrow. The flight is very evenly with no sudden movement-changes. On the ground, they move mostly hopping.

C. corone corone - sideview; the bird has approached.

C. corone corone lives in small swarms, which fuse with other swarms. This happens mostly in the evening, when the swarms look a place to sleep. At the beginning of the breeding season, male and female birds leave the swarm in pairs to built nests in trees or on electricity pylons. The average Breeding time are twenty days. The chicks have a brighter plumage and become fledge after four weeks. The maximum age of the Carrion Crow is about 19 years.

C. corone corone - the bird is very close and you can see
his face with the black iris

The birds are very intelligent and capable of learning. They have also a kind of self awarness.

The Carrion Crow is an omnivore, which eats everything from carrion (name) over berries and seeds to meat and insects. The birds search their food mostly on the ground. They look under stones and wood. If they have found something, which is to hard to eat (like a walnut), Carrion Crows take it with their beaks and drop it from a great high to crack it.

C. corone corone - view from above; the bird looks for
an old key, which lied beside the bench. 

Many people have difficulties to distinguish the Carrion Crow with the common raven (Corvus corax). But the Raven is much larger (average length: 64 centimetres) and has a cuneiform tail. The voice is also deeper.

C. corone corone - the plumage is a little bit bright.
maybe this is a younger bird or a hybrid.

C. corone is native to Europe and East Asia. The species is highly adaptable and have settled many different habitats like the edge of forests, farmland, cities and parks. It's a very common bird, which form massive stocks in some cities.

Today, the species Corvus corone is subdivided into two sub-species: the Carrion Crow and the Hooded Crow (Corvus corone cornix), which has a grey-black plumage. The Both sub-species are fully capable to mate and in regions with both sub-species, hybrids are very common.

Dienstag, 9. April 2013

Plant of the Day (April 9th, 2013) - Araucaria araucana (Molina) K. Koch

Today's “Plant of the Day” is a tree, which I planed to dedicate an own entry a long time ago but I didn't have enough pictures for a complete article. However, now I have and so, today's “Plant of the Day” is Araucaria araucana (Molina) K. Koch. The Genus of Araucaria is one of only three Genera within the family Araucariaceae. The other ones are Agathis (the largest genus) and the monotypic genus Wollemia (one species: Wollemia nobelis). All plants of the Araucariaceae are exotic conifers, which are native on the southern hemisphere. 

 A. araucana - habitus (young tree)
In German, A. araucana is known as “Chilenische Araukarie” or "Andentanne". In English, the species has many different names like “monkey tail tree” “Chilean pine” or “monkey puzzle tree”. In Spanish, the species name is “Pehuen” or “pienonero”.

A. araucana - bark

A. araucana is a large evergreen tree, which can reach a maximum height of nearly 40 metres (131.2 feet) in its native environment (however, the most individuals are between 8 and 15 metres (26.3 to 49.2 feet) high). The long stem has a smooth, grey bark with many round spots, which are the remains of older branches. The bark is very thick and protects the tree from fire caused by volcanic eruptions.
The branches are arranged in whorls with five branches per whorl. Young trees are branched to the ground, while grown-up trees only have branches at their tree crown. The whole crown has a characteristic pyramid-shape look.

A. araucana - branches

The hard leaves of A. araucana are triangular and scale-like. They have a leathery surface and a pointed apex. Thereby, branches are very sharp and can hurt you when hitting (trust me, I know what I'm talking about; it similar to a morning star ;-)). Leaves are arranged in a spiral leaf pattern and overlaps each other like roofing tiles (in Botany, such an overlapping is called imbricate). They have a dark green colour and are shiny. Stomata are on both sides; the leaves are amphistomatic.

A. araucana - leaves (ventral site

A. araucana is dioecious with male and female cones on different trees or monoecious with male and female trees at one tree. Male cones are upstanding and between 8 and 12 centimetres (3.2 to 4.7 inches) long and 5 centimetres (1.9 inches) broad. They spread their pollen during June but remain on the tree for months. They have a brown colour. Female cones are located at the end of the brnches. They are about 18 centimetres (7.1 inches) long and 20 centimetres (7.9 inches) broad. As you can see, they are more globular. Young cones have a golden yellow colour but become dark-brown during the ripening. When ripe, the cones break up and spread their seeds out. The seeds are bright brown and winged.

A. araucana - old male cone

The species is native to South America (Chile, Argentina) and grows in the Andes of South Chile and Patagonia. It has a very fine defined areal between 37° and 40° latitude and grows between 600 and 1600 metres (up to 5249 feet) altitude in mixed forest and pure stands. The whole tree is adapted to fire (thick bark, leathery leaves etc.), because there were and are many volcanoes in this area, which can cause bush fires. Because of its exotic habitus, A. araucana is also a very popular ornamental tree in Great Britain and Europe, where it's planted in parks and botanical gardens.

A. araucaria - leaves (ventral site) - please note the 
leaf-vein on the back and imbricate arrangement of the leaves

The wood is of high quality and was used to make houses, boats and bridges. However today, A. araucana is protected and it's not allowed to chop down trees any more, because strong logging had decimated the stock rapidly.

A. araucana is a living fossil and exists since the Cretaceous. However, the oldest, recent species of this family is Wollemia nobilis which exists since 90 Million years. This makes the Araucariaceae to one of the oldest tree-familes of the world.

Dienstag, 2. April 2013

Plant of the Day (April 2nd, 2013) - Erica arborea L.

The next “Plant of the Day” may look like a conifer, but is a flowering plant. This species is Erica arborea L. from the Ericaceae family (heaths). In German, the species is known as “Baumheide”, while the common English name is “tree heath”.

E. arborens - habitus

E. arborea is normally an evergreen and richly branched shrub, which can reach a height between 1 and 6 metres. (3.3 to 19.7feet). A maximum height of nearly 20 metres (nearly 66.6 feet) is also possible. This makes E. arborea to one of the largest Eriaceae of the world.

The most distinctive feature of this species is its conifer-like habitus which has a similarity to a cypress. This is also the reason for the Latin name: “Erica” means heath and “arborea” “tree-like”. The German and the English name are the literally translation of the Latin Name. The stems of young trees are covered with many, white hairs. 

 E. arborens - branches & leaves. bleas note the white
film on the brances, which are the white hairs of younger plants 

In consequence, the leaves are needle-like, only 5 millimetres long and arranged in whorls with 4 to 5 leaves per whorl. They have a bright green to medium green colour and a xerophyte morphology. For example, the margin is rolled, the surface is leathery and the cuticula thick.

E. arborens - same branc, closer look

The inflorescences are cyme-like with overhanging, bell-shaped flowers. They arise from the whorls of the bracts. Each flower has a long “flower stalk”, which is called Penducle in Botany. Sepals and petals are white, but the petals have a dark spot on their inside. Flowering time is between February and April. The ripe fruit is a drupe.

E. arborens - as ornamental tree on a cemetery

E. arborea is native to the Mediterranean, the Canary Islands and Central Africa. It's part of the laurel woods and marquis shrublands. This are very hot and dry regions, what is also the reason for the xeropmorphic habitus of the leaves and the white hairs, which protects young plants from dryness. Like the most heaths, this species prefers acidic places to grow.

The noble wood of E. arborea is very hard and resistant towards fire. It's also beautifully textured and has a unique, reddish brown color. Because of these properties, the wood is called bruyere in France and is used to make smoking pipes. The noble Bruyere is also used to make knive handles.