Wednesday, 9 August 2017
8-8-2017 NUREMBERG, GERMANY - HOUSE SPARROW (FEMALE) (Passer domesticus)
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The house sparrow (Passer domesticus) is a member of the sparrow family Passeridae. This small bird typically measures around 16 cm (6.3 in) in length and weighs between 24–39.5 g (0.85–1.39 oz). The species exhibits sexual dimorphism, with females and young birds displaying pale brown and grey plumage, while males are characterized by more vibrant black, white, and brown markings.
Males can be identified by their bright black, white, and brown markings, with a distinctive black bib, white cheeks, and a grey crown. Females lack the striking head patterns of males and are predominantly buffish with softer coloration. Juveniles resemble adult females but are generally paler with less defined markings.
The house sparrow is highly adaptable and can thrive in both urban and rural environments. It is commonly found in close association with human habitation and avoids dense forests, grasslands, polar regions, and deserts far from human development.
Native to Europe, the Mediterranean Basin, and much of Asia, the house sparrow has been introduced to various regions worldwide, including parts of Australasia, Africa, and the Americas, making it one of the most widely distributed wild birds.
Tuesday, 8 August 2017
30-7-2017 CENTRAL PARK, BUDAPEST - CRESTED OROPENDOLA (Psarocolius decumanus)
The crested oropendola, also known as the Suriname crested oropendola or the cornbird, is a striking member of the icterid family. Males are predominantly black with a chestnut rump and a vivid yellow tail, save for two central dark feathers. A distinctive feature is their long, narrow crest, which can be elusive to the observer's eye. The iris of this bird is a captivating blue, and the bill is a pale whitish hue. Females share a similar coloration but are smaller, less vibrant, and lack the male's crest.
To identify the crested oropendola, look for the male's long crest and the bright yellow of the tail, which contrasts with the black body and chestnut rump. The female is similar but smaller and without the crest. The blue iris and whitish bill are also key identification features.
This species is found in the forest edges and clearings, where it can be seen foraging among the trees.
The crested oropendola is a resident breeder in lowland South America east of the Andes, ranging from Panama and Colombia south to northern Argentina. It is also present on the islands of Trinidad and Tobago.
A colonial breeder, the crested oropendola constructs an impressive hanging woven nest, often exceeding 125 cm in length, high in the trees. The species exhibits some seasonal movements and is known to be quite mobile outside the breeding season. Dominant males perform an elaborate bowing display to attract females, with a single male mating with most females in a colony.
The male's song is a distinctive descending call, reminiscent of a hand sliding down a piano's keys. Both sexes emit a loud clack call, which is a notable part of their vocal repertoire.
The crested oropendola lays two blotched blue-grey eggs in its pendulous nest. The eggs hatch in 15-19 days, and the young fledge after an additional 24-36 days. Breeding colonies typically consist of 15-30 females and only 3-4 males.
While there are no specific similar species mentioned, it is important to note the differences in subspecies, which vary slightly in plumage details and distribution.
The diet of the crested oropendola includes large insects, fruit, seeds, and some nectar, which they forage for in trees.
The crested oropendola is classified as Least Concern by the IUCN, indicating that it currently faces no significant threats to its survival.
2-8-2017 CENTRAL PARK, BUDAPEST - RED POSTMAN BUTTERFLY (Heliconius erato)
Heliconius erato, or the red postman, is one of about 40 neotropical species of butterfly belonging to the genus Heliconius. It is also commonly known as the small postman, the red passion flower butterfly, or the crimson-patched longwing. It was described by Carl Linnaeus in his 1758 10th edition of Systema Naturae.
H. erato exhibits Müllerian mimicry with other Heliconius butterflies such as Heliconius melpomene in order to warn common predators against attacking, which contributes to its surprising longevity. It also has a unique mating ritual involving the transfer of anti-aphrodisiacs from males to females.
Recent field work has confirmed the relative abundance of this butterfly.
H. erato is a neotropical species, found from southern Texas to northern Argentina and Paraguay, and resides on the edges of tropical rainforests. It is philopatric, having a particularly restricted home range. In areas of dense population in Trinidad, some home ranges are only separated by 30 yards, but H. erato rarely travels to neighboring home ranges.
Larvae feed on the host plant, first consuming the terminal bud. After they have exhausted the resources of the plant they have hatched on, later instars may move to another plant.
H. erato is a pollen-feeding species, collecting from the Lantana camara flower. They do not spend much time or energy collecting nectar (only remaining for a few seconds). Instead, they collect pollen in a mass on the ventral side of their proboscis. They then agitate the pollen by coiling and uncoiling their proboscis in order to release its nutrients. H. erato is then able to extract nitrogenous compounds in a clear liquid, including amino acids like arginine, leucine, lysine, valine, proline, histidine, isoleucine, methionine, phenylalanine, threonine, and tryptophan. Females typically carry larger loads of pollen than males as females require more amino acids for egg production.
Previous studies have shown that host plants, such as Passiflora, have coevolved with Heliconius butterflies. Passiflora plants are usually found in low densities with even less plants in fruiting or flower conditions due to caterpillar feeding.[10] To increase chances of survival and cross-pollination, Passiflora plants synthesize toxins in leaves to deter Heliconius. Passiflora species produce different toxins, leading to different preferences for oviposition among Heliconius species. This leads to a lower chance of herbivore damage for individual Passiflora species and thus helps protect Passiflora plants. Chemical composition of toxins in such plants have not been studied widely. Studies have identified cyanogenic glycosides and alkaloids as potential chemicals that drive distasteful reactions among Heliconius. Toxin variation among Passiflora is one of the reasons for host specificity among Heliconius butterflies.
Studies have shown that H. erato species that feed on specific Passiflora species tend to spend more time on the host plant and are thus exposed to the toxins for a longer period. Accumulation of toxins such as cyanogenic glycosides leads to a low survival rate among H. erato larvae. Increasing exposure to parasitoids due to longer time spent on the host plant also contributes to the high mortality rate. One recent study showed that mortality increased among H. erato larvae which fed on cyanide-releasing Passiflora. Survived butterflies were capable of excreting higher levels of cyanides, suggesting a defense mechanism in H. erato.[14] H. erato species with more mechanisms to detoxify and secrete ingested toxins are the result of genetic differences among H. erato subspecies. Toxin excretion, from previous studies, results in changes in wing pattern and body size. Consequences include decreased fecundity, egg size, and survival rate.
Nectar excretion from Passiflora has also been studied as one factor which contributes to coevolution. Passiflora nectar is known to produce aggressive behaviors among ants, wasps, and egg parasitoids. Ehrlich and Gilbert have estimated that parasitoids are capable of destroying most Heliconius eggs under nectar influence. Therefore, host plants such as Passiflora are believed to have self-defense mechanisms that utilize predators against Heliconius butterflies.
2-8-2017 CENTRAL PARK, BUDAPEST - CHOCOLATE PANSY BUTTERFLY (Junonia iphita)
Junonia iphita, the chocolate pansy or chocolate soldier, is a butterfly found in Asia.
The wingspan is about 5–6 cm (2.0–2.4 in) and the female can be told apart from the male by white markings on the oblique line on the underside of the hindwing. The wavy lines on the underside of the wings vary from wet- to dry-season forms.
Individuals maintain a territory and are usually found close to the ground level and often bask in the sun.
Underside brown, with very broad darker brown transverse fasciae, the interspaces between the markings irrorated (sprinkled) with purplish silvery scales. Forewing with two sinuous fasciae on basal half succeeded by a discal fascia, very broad at the costal margin and decreasing in width to the dorsum, bearing on its outer border a row of obscure ocelli. This is succeeded by a zigzag dark line, and sinuous subterminal and terminal lines; apex and tornal area suffused with purplish silvery. Hindwing: two irregular, very broad, dark brown, curved short fasciae near base; a straight, transverse, prominent, narrow ochreous-brown discal band defined outwardly by a black line; a transverse postdiscal dark brown fascia, widest in the middle and bearing outwardly a curved row of ochreous-brown white-centred ocelli, followed by a zigzag dark line in continuation of the one on the forewing; a subterminal somewhat diffuse dark fascia and a terminal dark line. Antennae, head, thorax and abdomen dark brown..
The eggs are often laid on the ground or on dry twigs near the host plants rather than on them. On hatching the larvae find their way to the host plants.
Larva are "Cylindrical, slightly pubescent and armed with nine longitudinal rows of many-branched spines, except on the head which is clothed with short bristles. ... Colour dark dull brown." (Davidson and Aitken)
The pupa "is regular, with three or five dorsal rows of small tubercular points, hung perpendicularly. ... Colour smoky brown."(Davidson & Aitken)
8-8-2017 NUREMBERG, GERMANY - COMMON CUCKOO (Cuculus canorus)
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The common cuckoo (Cuculus canorus) is a member of the cuckoo order of birds, Cuculiformes, which includes the roadrunners, the anis and the coucals.
This species is a widespread summer migrant to Europe and Asia, and winters in Africa. It is a brood parasite, which means it lays eggs in the nests of other bird species, particularly of dunnocks, meadow pipits, and reed warblers. Although its eggs are larger than those of its hosts, the eggs in each type of host nest resemble the host's eggs. The adult too is a mimic, in its case of the sparrowhawk; since that species is a predator, the mimicry gives the female time to lay her eggs without being attacked.
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Monday, 7 August 2017
7-8-2017 RIVER DANUBE, REGENSBURG - COMMON MERGANSER (Mergus merganser)
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The Common merganser is a large seaduck that lives in forested areas of Europe, Asia, and North America. These birds eat mainly fish and nest in holes in trees.
The Common merganser has a crest of longer head feathers, but these usually lie smoothly rounded behind the head. Adult males in breeding plumage are easily distinguished; their body is white with a variable salmon-pink tinge, the head is black with an iridescent green gloss, the rump and tail are grey, and the wings are largely white on the inner half, and black on the outer half. Females and males in "eclipse" (non-breeding plumage) are largely grey, with a reddish-brown head, white chin, and white secondary feathers on the wing. Juveniles (both sexes) are similar to adult females but also show a short black-edged white stripe between the eye and bill. The bill and legs are red to brownish-red, brightest on adult males, and dullest on juveniles.
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Common mergansers are found in Europe, the northern and central Palearctic, and North America. These birds are partial migrants; they leave areas where rivers and major lakes freeze in the winter but are resident where waters remain open. Eastern North American birds move south in small groups to the United States wherever ice-free conditions exist on lakes and rivers; on the milder Pacific coast, they are permanent residents. Scandinavian and Russian birds also migrate southwards, but Western European birds, and a few in Japan, are largely resident. Common mergansers breed in forested areas near freshwater lakes, rivers, pools, and streams. During the summer they inhabit lakes, rivers, reservoirs, brackish waters, and marshes. They try to avoid saltwater but may be found in estuaries, coastal bays, and lagoons.
Common mergansers are carnivores (piscivores). They feed mainly on fish but also hunt a wide range of other aquatic prey, such as mollusks, crustaceans, worms, insect larvae, and amphibians. More rarely, they will take small mammals and birds.
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Common mergansers are diurnal birds that usually do their hunting in the early morning, in the afternoon, and before sunset. When not diving for food, they are usually seen swimming on the water surface, or resting on rocks in midstream; they may also hide among riverbank vegetation, or (in winter) on the edge of floating ice. In larger streams and rivers, Common mergansers float down with the stream for a few miles, and either fly back again or more commonly fish their way back, diving incessantly the whole way. In smaller streams, they are present in pairs or smaller groups, and they float down, twisting round and round in the rapids; they also fish vigorously in a deep pool near the foot of a waterfall or rapid. When floating leisurely, they position themselves in water similar to ducks, but they also swim deep in water like cormorants, especially when swimming upstream. They often sit on a rock in the middle of the water, similar to cormorants, often half-opening their wings to the sun. To rise from the water, they flap along the surface for many yards. Once they are airborne, the flight is strong and rapid. Their ordinary voice is a low, harsh croak, but during the breeding season, mergansers (including the young) make a plaintive, soft whistle. Generally, they are wary, and one or more birds stay on sentry duty to warn the flock of approaching danger. When disturbed, Common mergansers often disgorge food before moving. Though mergansers move clumsily on land, they resort to running when pressed; they assume a very upright position similar to penguins and frequently fall and stumble.
Common mergansers are monogamous and form pairs that usually last for at least one breeding season. They breed in the summer and nest normally in a tree cavity; they also readily use large nest boxes where provided, requiring an entrance hole 15 cm (5.9 in) in diameter. In places devoid of trees (like Central Asian mountains), they use holes in cliffs and steep, high banks, sometimes at considerable distances from the water. The female lays 6-17 (most often 8-12) white to yellowish eggs and raises one brood in a season. Incubation lasts 28 to 35 days done only by the female. The ducklings are born precocial and are taken by their mother in her bill to rivers or lakes immediately after hatching; there they feed on freshwater invertebrates and small fish fry. Fledging usually occurs when ducklings are between 60 and 70 days old and reproductive maturity is reached at the age of two years.
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