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Migration Calendar

Track bird migration patterns

Explore when migratory birds arrive and depart from your region. View seasonal migration calendars, flyway maps, and timing data for hundreds of migratory species.

p.bird__slug === this.selectedBird); if (this.selectedCountry) ps = ps.filter(p => p.country__code === this.selectedCountry); const monthSet = new Set(); ps.forEach(p => (p.months_present || []).forEach(m => monthSet.add(m))); return Array.from({length:12}, (_,i) => monthSet.has(i+1)); }, get migratoryInfo() { if (!this.selectedBird) return ''; const ps = this.presences.filter(p => p.bird__slug === this.selectedBird); const statuses = [...new Set(ps.map(p => p.migratory_status))]; return statuses.join(', '); }, get birdObj() { return this.birds.find(b => b.slug === this.selectedBird); } }">

Calendario de migración

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Explore when migratory birds arrive and depart from your region. View seasonal migration calendars, flyway maps, and timing data for hundreds of migratory species.

Migration Herramienta gratuita Interactivo

Aves destacadas

Abejaruco Europeo

Merops apiaster

Abubilla

Upupa epops

Águila Arpía

Harpia harpyja

Águila Calva

Haliaeetus leucocephalus

Águila real

Aquila chrysaetos

Albatros Errante

Diomedea exulans

Alcatraz Atlántico

Morus bassanus

Amazona Frentiazul

Amazona aestiva

Ánade Real

Anas platyrhynchos

Arrendajo Azul

Cyanocitta cristata

Ave del Paraíso de Raggiana

Paradisaea raggiana

Ave del Paraíso de Wilson

Cicinnurus respublica

Avestruz Común

Struthio camelus

Azulejo Oriental

Sialia sialis

Búho Cornudo

Bubo virginianus

Búho Nival

Bubo scandiacus

Búho Real

Bubo bubo

buitre leonado

Gyps fulvus

busardo colirrojo

Buteo jamaicensis

Cacatúa ninfa

Nymphicus hollandicus
← Todas las herramientas

How to Use

  1. 1
    Set your location and target year

    Enter your geographic coordinates or select your region to access locally relevant migration timing data. Peak passage dates vary substantially with latitude, so location specificity is essential for accurate phenology information.

  2. 2
    Browse species by migration period

    Navigate the calendar by month to see which species groups are moving through your area during spring and autumn passage. Note that spring migration is typically more compressed and predictable in timing than the more protracted autumn movement.

  3. 3
    Plan observation sessions at peak times

    Identify the predicted peak passage windows for target species and plan field visits accordingly, particularly to stopover habitats like coastal headlands, river valleys, and woodland edges where migrants concentrate. Dawn hours typically produce the highest activity as nocturnal migrants descend to refuel.

About

Bird migration is one of the most spectacular phenomena in natural history, involving billions of individual birds moving seasonally between breeding and non-breeding areas along routes shaped by millions of years of evolutionary history. The study of migration—covering its mechanisms, timing, ecology, and conservation implications—has advanced dramatically with the development of miniaturized tracking technology and global citizen science networks.

Migration phenology—the timing of seasonal movements—is highly species-specific and reflects evolutionary optimization of arrival at breeding grounds coinciding with peak food availability while minimizing exposure to harsh conditions. The bar-tailed godwit holds the record for non-stop migratory flight, covering over 11,000 km from Alaska to New Zealand without feeding, burning nearly half its body mass as fuel. At the other extreme, altitudinal migrants like many mountain thrushes move only a few hundred meters vertically between summer and winter ranges. Between these extremes lies a continuous spectrum of migration strategies shaped by the ecology of each species.

Stopover ecology is a critical but historically underappreciated component of migration biology. Migrants must accumulate sufficient fuel reserves at stopover sites to continue their journeys, making the availability of food and safe resting habitat at strategic locations essential to population viability. Coastal headlands, river valleys, and isolated woodlands surrounded by inhospitable terrain act as concentration points where migrants accumulate during passage, creating exceptional birdwatching opportunities and conservation priorities. Understanding stopover site quality and its relationship to migratory success has become a major research focus as habitat loss along flyways accelerates.

FAQ

How do birds navigate during long-distance migration?
Birds employ a multi-cue navigational system integrating magnetic sensing, celestial orientation, and learned landmarks to achieve extraordinary positional accuracy over intercontinental distances. Cryptochromes in the retina are sensitive to Earth’s magnetic field, providing both a compass and potentially a map sense based on field inclination and intensity. The star compass, calibrated against the rotation axis of the sky during early development, provides directional information on clear nights. Sun compass orientation compensates for the sun’s diurnal movement using an internal circadian clock. Olfactory mapping has been demonstrated in some seabirds. These systems are integrated hierarchically, with magnetic information typically dominating in overcast conditions when celestial cues are unavailable.
Why do birds migrate at night?
Nocturnal migration is the dominant strategy among small passerines, offering multiple advantages over daytime movement. Cooler nighttime temperatures reduce overheating risk during sustained flapping flight and allow daytime hours to be devoted to foraging and refueling at stopover sites. Predation risk from raptors is reduced at night, though owls and other nocturnal predators still take migrants. Thermal convection during the day creates turbulent conditions unfavorable for sustained directional flight in small birds, whereas nocturnal atmospheric stability supports more efficient laminar airflow. The celestial star compass requires darkness to function optimally. Radar studies have documented that the vast majority of small songbird migration occurs between sunset and midnight, with a secondary peak just before dawn.
What triggers migration in birds each season?
Migration is initiated by endogenous annual programs—internal circannual rhythms—calibrated and fine-tuned by photoperiodic cues. Increasing day length in late winter activates the hypothalamic-pituitary-gonadal axis, elevating gonadotropin-releasing hormone and inducing fattening, molt, and migratory restlessness (Zugunruhe). Temperature, food availability, and social cues act as proximate modifiers that can accelerate or delay departure within the range permitted by the photoperiodic program. In autumn, decreasing day length combined with completed breeding and post-breeding molt triggers southward migration. Long-distance migrants relying on photoperiod are increasingly mismatched with food availability at breeding grounds as climate change alters spring phenology faster than genetically programmed arrival times can respond.
What are flyways and why are they important for conservation?
Flyways are broad geographic corridors used by migratory birds linking breeding, stopover, and wintering areas across continents. The eight principal flyways recognized by conservation organizations—including the East Atlantic, Mississippi, and East Asian-Australasian Flyways—channel millions of birds through shared networks of wetlands, coastal habitats, and forest patches. Because migratory species depend on the integrity of habitats at multiple points along their route, conservation must occur at flyway scale rather than focusing only on breeding or wintering areas. International agreements like the African-Eurasian Migratory Waterbird Agreement (AEWA) and the Ramsar Convention on Wetlands provide frameworks for flyway-scale protection. Bottleneck sites where migrants concentrate become critical conservation priorities because degradation of a single strategic stopover can affect entire flyway populations.
How is climate change affecting bird migration patterns?
Long-term dataset analyses consistently demonstrate that spring migration arrival dates are advancing in many species as breeding ground conditions warm earlier. However, the rate of phenological advance varies among species, creating mismatches between migrant arrival and peak food availability—particularly insect emergence—at breeding sites. Species that winter in sub-Saharan Africa and rely on photoperiodic cues for departure are constrained in their ability to advance migration, while short-distance migrants relying more on temperature cues show greater phenological plasticity. Some species are expanding their ranges northward, colonizing previously unsuitable habitats. Extreme weather events associated with climate change, including late cold snaps and intense storms, increasingly affect migrant survival. Autumn migration timing shows less consistent trends than spring arrival, complicating overall assessment of climate impacts.