Mombach nesting course
The Mombacher Nist-Parcours creates new living and nesting cavities for native bird species, bats and dormice, such as garden dormice and edible dormice. The targeted installation of artificial nesting aids, roosts and retreats makes an important contribution to the conservation of protected and endangered species.
The Mombach Bird Nesting Trail runs along Käthchen-Frödert-Weg and continues straight ahead along Obere Kreuzstraße toward Mainzer Sand. There you can discover the 17 bird nesting aids.
Habitats & species protection
The individual sites offer habitats typical of the various species, ranging from wooded areas and open parks to open landscapes dotted with scattered trees characteristic of the adjacent Mainz Sand.
Especially in times of climate change, increasing land consumption, and the decline of natural habitats, such nature-oriented projects are becoming increasingly important. The nesting trail combines species conservation with environmental education and invites nature enthusiasts and walkers to consciously observe and protect local wildlife and its ecological needs.
In addition to the goal of sustainably promoting biodiversity, strengthening existing populations, and developing new habitats—including within urban settlement areas—the project aims to be a place of encounter, learning, and enthusiasm for nature and the environment for all generations.
Project cooperation
The project is part of the implementation of the city’s biodiversity strategy, carried out in cooperation between Lernen Fördern TG Rheinland-Pfalz gGmbH and the Department of Parks and the Environment of the State Capital of Mainz.
Animal species profiles
Blue tit
The blue tit (Cyanistes caeruleus) is a small songbird measuring about 11.5 centimeters in length, notable for its blue crown, blue tail feathers, and bright yellow breast. As a social species, it is often seen in flocks outside the breeding season, foraging together.
Its habitat includes gardens, forests, and parks, preferably near meadows. In Germany, the blue tit is resident year-round and occurs both as a resident bird and as a short-distance migrant. Part of the population winters in milder regions of Central Europe or in the western Mediterranean.
The breeding season runs from April to June. During this time, the blue tit uses various sheltered nesting sites, including tree cavities, crevices, abandoned woodpecker holes, rock crevices, and cavities in buildings. The species is currently considered not endangered and is one of the most common bird species in Central Europe.
Brown long-eared bat
The brown long-eared bat (Plecotus auritus) is one of the smaller native bat species, with a body length of about 4–5 cm and a wingspan of 24–29 cm. It is characterized by its exceptionally long ears, which give it its name. The fur on its back is long, loose, and brownish-reddish in color, while its underside appears cream-colored; its face is light brown.
The species is strictly nocturnal and is characterized by a slow yet extremely agile flight. Thanks to its large ears, it possesses very precise echolocation, which even allows it to hover or fly backward briefly. The brown long-eared bat lives a predominantly secretive and reclusive life. In summer, several females form so-called nursery roosts, where a single young is born after a gestation period of about 40 to 70 days—usually in June or July.
The species prefers forests as habitats but also uses parks, gardens, cemeteries, and orchards. Summer roosts are often found in tree hollows, nest boxes, and in buildings such as attics or wall crevices. In winter, the brown long-eared bat retreats to frost-protected roosts such as caves, tunnels, or cellars and hibernates from October or November until around March. It exhibits a pronounced tendency to remain in the same area: summer and winter roosts are usually less than 10 kilometers apart.
In Germany and parts of Europe, the brown long-eared bat is considered endangered, while globally it is not currently classified as threatened.
Garden treecreeper
The short-toed tree creeper (Certhia brachydactyla) is a small, inconspicuous songbird with a body length of about 12 to 13 centimeters. Due to its camouflage coloring, it is often overlooked, even though it is widespread in many areas.
Its upperparts are dark brown and speckled with fine white spots. This pattern serves as camouflage, allowing it to blend in visually with tree bark. The underparts are predominantly white, while the coloration transitions to a lighter brown toward the tail. A striking feature is its long, slightly downward-curved beak, which is perfectly adapted to its diet. The wings display a light beige, stepped plumage.
The garden tree creeper is strongly tied to wooded habitats. It is found primarily in deciduous forests as well as in parks and gardens, provided there are older trees with rough, cracked bark—such as oaks, ash trees, or old fruit trees. These structures are important because the bird picks insects and spiders from the bark there.
A typical behavior is its spiral climb up tree trunks. As it does so, it uses its tail for support and systematically searches the bark for food.
The species is currently considered not endangered, as it is adaptable and maintains stable populations in suitable habitats.
Redstart
The redstart (Phoenicurus phoenicurus) is a songbird measuring 13 to 15 cm in length with pronounced sexual dimorphism. The male has ash-gray plumage, a black throat, and a striking orange breast; other characteristic features include a conspicuous rust-red tail and a white forehead. The female, on the other hand, is more inconspicuous overall, with gray-brown plumage, a lighter underparts, and a distinctly reddish-brown tail.
Ecologically notable is its behavior as a perching hunter: The bird remains on an elevated perch, observes its surroundings, and then launches short, rapid hunting flights to capture prey—mostly insects. A typical feature of this behavior is the frequent quivering of the tail.
The redstart is a distinct long-distance migrant and winters in Africa. It prefers open deciduous and mixed forests, particularly pine forests, as well as parks and natural gardens.
In Germany and parts of Europe, the species is listed on the early warning list, indicating potential population declines. Globally, however, the redstart is currently not considered endangered.
Garden dormouse
The garden dormouse (Eliomys quercinus) is a medium-sized member of the dormouse family, with a body length of 12–17 cm and a tail length of 10–14 cm. A distinctive feature is its striking black facial markings, known as the “Zorro mask.” The fur on its back is reddish-brown to gray, while its flanks and underside are distinctly white.
The species is nocturnal and lives primarily alone. Garden dormice are opportunistic feeders—eating whatever is available, whether animal or plant matter, including insects, worms, snails, as well as fruits and seeds. Reproduction occurs in the spring: after a gestation period of about 21 days, the female typically gives birth to 4 to 6 young in May, which she raises alone.
Sheltered and quiet structures such as bushes, tree hollows, deadwood, or niches serve as nesting sites. From October to April, the garden dormouse hibernates to survive the food-scarce season.
In Germany, the species is primarily found in the western lowlands as well as in the low mountain ranges of the central and eastern regions, but it also occurs in other parts of Europe. Despite this distribution, the garden dormouse is considered critically endangered in Germany and in large parts of Central, Southern, and Eastern Europe, or is already regionally extinct. Globally, it is currently listed on the Early Warning List, indicating an alarming decline in population.
Gray flycatcher
The Spotted Flycatcher (Muscicapa striata) is a songbird measuring 13 to 15 centimeters in length with rather drab plumage. Its appearance is characterized by gray upperparts, a pale, whitish belly, and a chest with fine gray streaks. The forehead is darker in color, and the beak appears black.
As a perching hunter, the Spotted Flycatcher remains on an exposed perch and launches short, rapid dives from there to catch flying insects.
They are distinct long-distance migrants. While they can be found in Central Europe during the summer months, they winter from October to March south of the Sahara, as far south as South Africa. The Spotted Flycatcher prefers open deciduous, coniferous, and mixed forests as its habitat, particularly forest edges and clearings with sufficient sunlight. It is also found in structurally diverse urban areas such as residential neighborhoods, cemeteries, and parks.
The breeding season extends from May to July. The Spotted Flycatcher shows great flexibility in its choice of nesting sites and uses, among other things, tree cavities, forked branches, holes in walls, climbing plants, old swallow nests, and sheltered areas on buildings such as behind shutters or in window boxes. The female typically lays 4 to 6 whitish eggs with a greenish-blue tint and brown spots, which are incubated over a period of 12 to 15 days.
In Germany, the Spotted Flycatcher is listed on the early warning list, while globally it is currently still considered not endangered.
Greater mouse-eared bat
With a body length of 6.8 to 8 cm and a wingspan of about 40 cm, the greater mouse-eared bat (Myotis myotis) is the largest native bat species in Germany. It is characterized by its yellowish-brown back fur and whitish underparts. The face has a pink to flesh-colored hue and is covered with glands. Also striking are the large, similarly flesh-colored ears with a narrow, pointed tragus that reaches about half the length of the ear. The wings are dark brown in color.
The species is nocturnal and hunts both in flight and by gathering prey from the ground. This dual hunting strategy allows for a broad diet. In summer, several females gather in nursery roosts, where, after a gestation period of about 60 days—usually in June—a single young is typically born, though twins are occasionally seen.
Warm attics, particularly in churches, serve as preferred summer roosts. The preferred habitat also includes forests with sparse ground vegetation, which offer optimal conditions for foraging. The Greater Mouse-eared Bat is widespread in Germany, with a concentration in the south, and is also found throughout much of Europe.
In winter, the species retreats to caves and tunnels and hibernates from October to April. It exhibits a strong sense of site fidelity: summer and winter roosts are usually located within a maximum distance of about 50 kilometers. Despite regional threats, the Greater Mouse-eared Bat is currently considered not endangered overall.
Black redstart
The black redstart (Phoenicurus ochruros) is a small songbird with a body length of about 13 to 15 centimeters. It is a typical synanthropic species, meaning it is commonly found in human settlements or agricultural areas. It is therefore not only found in natural habitats such as forests or rocky areas.
There it often finds favorable conditions—for example, more food, nesting sites, or fewer natural predators. In some cases, it even remains year-round.
Otherwise, the local populations are short- and medium-distance migrants that overwinter in the Mediterranean region. It is notable that the Black Redstart is among the first bird species to return in the spring: It often arrives back in its breeding grounds as early as late February and also remains in the area for a relatively long time in the fall.
It prefers to use sheltered structures such as caves, rock crevices, and niches in buildings and agricultural structures as nesting sites. The breeding season extends from April to July, with usually two broods per year. The female typically lays three to six whitish eggs, which are incubated for about 12 to 13 days.
There is a distinct sexual dimorphism: the male has predominantly gray-black plumage, while females and young males are gray-brown in color. Characteristic of both sexes are the reddish tail feathers. Also typical of the species is frequent bobbing of the head and the conspicuous wagging of the tail.
The redstart feeds mainly on insects, spiders, and other small invertebrates. It often hunts from the ground or from elevated perches, from which it swoops down on its prey.
Nuthatch
The Eurasian nuthatch (Sitta europaea) is a songbird measuring 12 to 14.5 centimeters in length with distinctive plumage: a white face with a prominent black stripe across the eyes, a blue-gray back, and a warm orange belly.
As a diurnal bird, the nuthatch is distinguished by its unique climbing behavior. It moves jerkily along tree trunks and rocks and is one of the few birds capable of climbing headfirst downward. Another distinctive feature is its feeding technique: nuts are wedged into cracks in the wood and then cracked open with the beak.
Its diet varies by season: while it mainly eats insects during the warmer months, its diet in winter consists primarily of nuts and seeds. The nuthatch is resident in Germany year-round and prefers open deciduous and mixed forests, but is also found in parks, large gardens, tree-lined avenues, cemeteries, and orchards. The species is currently considered not endangered.
Great Tit
With a body length of about 13.5 to 15 centimeters, the great tit (Parus major) is the largest tit species in Germany. It is easily recognizable by its distinctive appearance: its head is glossy black with striking white cheek patches. The underparts are a bright yellow color, crossed by a black longitudinal stripe, while the back is moss green.
The great tit prefers habitats rich in structure with trees and shrubs, including deciduous and mixed forests as well as parks and gardens near settlements. It is both a resident bird and a short-distance migrant and can therefore be observed year-round in Germany. Most great tits remain in their habitat even in winter; only a few young birds migrate sporadically to warmer areas.
Dormouse
The dormouse (Glis glis) is a medium-sized shrew with a body length of 13–14 cm and a tail length of 11–15 cm. It is characterized by its dense, gray-blue fur, white belly, and large, black eyes. Its long, bushy tail helps it maintain balance in the branches.
The species is predominantly nocturnal and lives a secluded, solitary life. Thanks to suction cups on its feet, the dormouse is an excellent climber and moves confidently through the treetops. Its diet consists mainly of plant matter such as (tree) fruits, buds, shoots, and leaves.
Reproduction occurs in the summer: after a gestation period of about 28 days, the female typically gives birth to 4 to 6 young in July or August, which she raises on her own. A striking characteristic of the species is its long hibernation, which lasts from October to May and thus spans a large part of the year.
The dormouse prefers structurally diverse deciduous and mixed forests as well as orchard meadows. In Germany, its primary range lies south of the low mountain ranges; beyond that, it is found in large parts of Europe and as far as Asia.
Star
The starling (Sturnus vulgaris) is a songbird measuring 19 to 22 centimeters in length with a distinctive appearance: At first glance, its plumage appears black, but depending on the angle of the light, it displays a striking violet-green metallic sheen and is speckled with fine white spots. Its beak is yellow.
As an adaptable omnivore, the starling feeds primarily on insects and fruit, but flexibly adapts its diet to the prevailing environmental conditions.
Outside the breeding season, it is extremely sociable and often forms large flocks that are notable for their synchronized flight movements.
The starling is resident in Germany year-round, though part of the population migrates as short-distance migrants to milder regions of Central Europe or the western Mediterranean. Its habitat includes gardens, forests, and parks, preferably near meadows. While the global population is considered stable, the starling is classified as endangered in Germany.
Little owl
The little owl (Athene noctua) is a small, stocky owl species with a body length of 21 to 23 cm. Its plumage has a brown base color on the upper parts with numerous white spots, while the underparts are white with brown longitudinal stripes. Another characteristic feature is the distinctive white stripes above the eyes, which resemble “eyebrows.”
In terms of behavioral ecology, the little owl exhibits a pronounced diurnal activity compared to other owl species: it often perches on exposed vantage points during the day and observes its surroundings. It possesses a good spatial memory, which enables it to effectively memorize hiding spots and locate them quickly. The species is sedentary and can be found year-round in Germany, without any distinct migratory behavior.
The little owl prefers open, structurally diverse landscapes such as fields, meadows, and gardens with shrubs and trees. The breeding season extends from April to May. It nests in building niches, stone walls, tree hollows, and rock faces. The female typically lays 2 to 6 roundish white eggs, which are incubated for about 28 days.
In Germany and some other countries, the little owl is classified as endangered, primarily due to habitat loss.
Marsh tit
The marsh tit (Poecile palustris) is a small songbird with a body length of about 11.5 to 13 cm. It is characterized by brown upperparts and pale to beige underparts. Distinctive features include a glossy black crown, contrasting pale cheeks, and a black chin patch.
The species exhibits a pronounced hoarding behavior, hiding food to fall back on during times of scarcity. Another socially notable trait is the long-term pair bond; the young birds also remain with the family group for a relatively long time before becoming independent.
The breeding season extends from March to June. Tree cavities or artificial nest boxes are preferred nesting sites. The female typically lays 6 to 10 dull, off-white eggs with brownish-red speckles, which are incubated over a period of about 12 to 15 days. The marsh tit is currently not considered endangered, although regional population fluctuations can be observed.
Tawny owl
The tawny owl, also known as Strix aluco, is a medium-sized, compact, and robust owl species with a body length of 37 to 43 centimeters.
Its plumage varies between rust-brown and gray-brown hues and features a characteristic pattern of droplet-shaped spots and fine longitudinal streaks, which provide excellent camouflage in the forest. Distinctive are the two whitish eyebrows on its face, while it lacks tufted ears. The underside of the body is always lighter than the upper side.
As an adaptable species, the tawny owl inhabits not only deciduous and mixed forests but also parks and areas near human settlements. It is widespread throughout Germany, with a concentration in the low mountain ranges, and is also found in large parts of Europe (with the exception of northern Scandinavia) as well as in parts of North Africa and Asia.
Hoopoe
The hoopoe (Upupa epops) is a bird measuring about 26–29 cm in length, with a distinctive long, slightly curved, dark beak. Its orange-brown head, nape, and throat are particularly striking, as is the erectile crest with black tips that gives the species its name. The back and wings display a distinctive black-and-white banding, while the tail feathers are predominantly black.
It feeds primarily on larger insects and their larvae, supplemented by spiders, earthworms, and occasionally small vertebrates such as lizards. Foraging takes place mainly on the ground, where it pokes the ground with its beak. A distinctive behavior is displayed when threatened: females and young birds can secrete a foul-smelling substance that deters potential predators.
The hoopoe is a long-distance migrant and winters in tropical regions of Africa as well as in the Sahel. It prefers semi-open to open, insect-rich landscapes such as vineyards, orchard meadows, and slopes with sparse vegetation.
In Germany and parts of Europe, the species is considered endangered; regionally, it has already disappeared or is threatened with extinction.
Pipistrelle bat
With a body length of about 5 cm and a wingspan of around 20 cm, the common pipistrelle (Pipistrellus pipistrellus) is one of the smallest bat species in Germany, alongside the soprano pipistrelle. It has short ears, a narrow wing profile, and distinctive fur: its back is blackish-brown, while its underside appears lighter, grayish-brown.
Its diet consists mainly of small moths, mosquitoes, and flies. The pipistrelle often begins hunting at dusk and is therefore relatively easy to observe even in low light. Its flight is fast and extremely agile. Like all bats, it uses echolocation for navigation and locating prey: it emits ultrasonic sounds inaudible to the human ear and interprets the returning echoes. Additionally, it produces audible calls used for social communication.
In summer, several females gather in nursery roosts. The species exhibits a strong sense of site fidelity; summer and winter roosts are generally less than 50 kilometers apart. The pipistrelle bat inhabits a wide range of habitats, including cities, villages, and adjacent parks and forests.
The pipistrelle can be found throughout almost all of Germany.

















