Animals

At station 22, the 2016–2017 report recorded six fish: barbo-comum, boga-do-Norte, escalo-do-Norte, bordalo, góbio and perca-sol, using their Portuguese common names. The station profile places it in Cavez. These results document that survey; they are neither a current inventory nor directions to fishing spots.

The six names open six ways of looking at the river. The barbel leads to migration within fresh water; the nase to differences between young and adult fish; the chub to scale patterns. The bordalo and gudgeon help explore diet. The pumpkinseed introduces geographical origin. Open the cards to choose a clue and reach the species explanation.

Sampling surveys and biological profiles serve different purposes. The survey documents fish recorded at that place and time. The profiles explain general species characteristics, without demonstrating that all these behaviours were observed in Cavez. Read both together while keeping that distinction.

The European nightjar feeds on insects and becomes active at dusk and during the night. Its continuous song can resemble a cicada’s sound. In Portugal it is a summer visitor, associated mainly with the north and the transition between woodland and open spaces. The Cavez record shows a feather attributed to this species by the iNaturalist community. It is a trace: not a photograph of the whole bird or proof of a nest at that point. Curiosity begins with a feather and continues into the soundscape.

Long wings and a long tail may be visible in silhouette, but low light hides details. The Aves de Portugal profile explains that females lack the white wing patches of males; juveniles lack them too. The absence of a mark alone does not determine age and sex.

The source describes a late arrival, with song easier to detect in May and June. This is a Portuguese pattern, not a sightings calendar for Cavez. The recorded feather cannot tell us when the bird sang, where it nested or how long it stayed in the area.

To understand journeys, researchers need another kind of record. The BTO presents tracking studies that located an important wintering area in grassland and shrub landscapes south of the equatorial forest, mainly in the Democratic Republic of the Congo. This information concerns birds tracked in those studies, not a demonstrated destination for the bird associated with the Cavez feather. A feather documents a trace in one place; tracking connects positions over time to study movements.

Fluviário de Mora describes the breeding migration of the Iberian barbel, Luciobarbus bocagei, to shallow, well-oxygenated water over sand, gravel or pebbles. It is a freshwater journey. The fish feeds on small bottom-dwelling animals, plant matter and detritus. Barbel were recorded in Cavez during the 2016–2017 survey; the behaviour described is general biology, not a migration observed at that point.

The journey does not contradict its preference for slower currents and moderate temperatures. The place used for living and feeding can differ from the one chosen for reproduction. The Fluviário profile places breeding between May and June as a general description of the species.

The barbel is omnivorous: besides bottom-dwelling invertebrates and plant matter, it may occasionally eat small fish. The same source notes that it can reach about one metre. This is a possible size for the species, not a measurement of the Cavez specimens.

The Douro nase, Pseudochondrostoma duriense, is native to the Iberian Peninsula. Santa Maria da Feira’s municipal profile describes adults in strong-current river sections and juveniles preferring slower water and fine substrates. It also mentions upstream movements before reproduction. The Cavez record from 2016–2017 confirms the species in that survey; it does not describe the sampled fish’s ages or behaviour.

There is a clue in the mouth: the lower lip is straight and has a well-developed horny edge. The body may show small dark spots. These features complement the habitat story; they do not replace careful identification.

The municipal source places upstream migrations between March and June and gives an approximate lifespan of six years. Upstream means towards the source. The calendar and lifespan describe the species in general, without dating a movement or determining the age of fish sampled in the Tâmega.

The pumpkinseed, Lepomis gibbosus, originates from North America. The Águeda River Interpretation Centre describes it as a non-native species with a deep, laterally flattened body, living in still water but also in rivers. During breeding, males may make it harder for juveniles of native species to reach bank shelters. It was recorded in Cavez in 2016–2017; that record does not measure its local impact.

Bluish bands from the head to the flanks and a dark spot at the edge of the gill cover are part of the description. Juveniles have a simpler pattern on a greenish or olive background. Age also changes appearance.

The menu includes insects, crustaceans, gastropods and fish larvae. This variety helps show that its diet is not limited to one prey. The profile also distinguishes lentic environments, such as reservoirs, from lotic environments, such as rivers and streams: the species can use both. Geographical origin, presence in a survey and effects on other species are different kinds of information.

The ICNF profile describes the bordalo, the Squalius alburnoides complex, as feeding mainly on insect larvae. In summer and early autumn it notes greater consumption of terrestrial insects. This makes a small connection between the river and its banks. The bordalo appears in the Cavez study from 2016–2017 under the name Iberocypris alburnoides; the local study did not analyse this seasonal dietary change.

The same profile describes the use of rivers and streams with varied features, including small, shallow watercourses with emergent aquatic vegetation. Habitat is not just water: shelters, vegetation and alternating areas of different current speeds also enter the story.

A completely bare bank therefore changes more than the view. The profile links loss of riverside vegetation with reduced shade, shelter and feeding places. These general ecological relationships help interpret the river; they are not a current assessment of a Cavez river section. The local 2016–2017 record and the biological explanation answer different questions: where the fish was documented, and how it relates to its environment.

The Arouca Geopark profile describes Squalius carolitertii with an elongated body, a large rounded head and scales with darker edges that create a net-like pattern. It presents the fish as endemic to Iberia: its natural distribution belongs to the Iberian Peninsula, not just Cabeceiras.

The description mentions mountain and lowland rivers, reminding us that one species can occupy different settings along the river network. These general features help introduce the fish; they are not enough to identify an individual from a distance.

The local connection comes from another source: the northern Iberian chub appears in the Cavez sampling survey from 2016–2017. The report documents that survey without establishing current presence or abundance.

The Geopark profile gives a maximum length of 25 centimetres and a breeding season between April and June. It describes the dorsal fin with a straight outline and the anal fin with a convex one. These are details to compare in a suitable illustration or photograph, not dimensions or dates measured during the Cavez survey. The spindle-shaped body, broader in the middle and tapered at the ends, completes this small exploration of form.

Parque Biológico de Gaia describes Gobio lozanoi as a freshwater river fish that eats small invertebrates and usually measures about 12 centimetres. That is a typical size given in the profile, not the size of every individual or a measurement taken in Cabeceiras.

In the Cavez survey from 2016–2017, the gudgeon is among the six species recorded. Bringing that evidence together with its diet description invites a question about the river: which small animals sustain the fish? The profile does not identify the prey eaten at that point or demonstrate a relationship with every insect presented on this website.

In David Matos’s photograph, the bird is perched beside water and a rocky surface. The record, dated 12 August 2024, is located in Cavez when its public point is compared with CAOP2025, and is identified as Motacilla cinerea. The long tail and yellow underside are details visible in this image.

The BTO describes a species associated mainly with fast-flowing water, which also uses slower rivers and the edges of lakes and ponds as it searches for aquatic insects. The habitat is more than a backdrop: it can provide food. The local photograph does not show a capture, so it cannot tell us what this bird ate during that encounter.

Compare it with the white-throated dipper: two birds associated with watercourses can find food in very different ways.

João Lima photographed this snail on 15 May 2024. The record is identified as Cepaea nemoralis, and comparing its published point with the CAOP2025 boundaries places it in Cavez. In the image, dark bands follow the shell’s whorls among wet leaves.

The Carnegie Museum of Natural History describes a shell that can have bands of different widths or no bands at all. The lip of the opening is usually brown, but not always. The species can also be confused with Cepaea hortensis. Colour, pattern and shape need to be considered together; a photograph that hides the opening leaves some clues out of sight.

Try following the spiral with your eyes. You do not need to move the animal to discover a pattern.