Absconding vs. Swarming: When Bees Leave the Hive

There's a particular kind of beekeeping heartbreak that begins with lifting an outer cover and finding nothing underneath. No cluster. No bees flying in or out. No hum. Just empty comb - maybe some capped honey still glistening in the frames, maybe some abandoned brood that dried out in the cells, maybe a few small hive beetles already moving in to colonize the vacancy.

The bees are gone. Not dead - there are no corpses on the bottom board. Gone. The entire colony packed up and left.

This is absconding, and it is not the same thing as swarming.

The Distinction

Swarming is reproduction. The colony divides. Roughly half the workers and the old queen depart. The other half stays behind with capped queen cells, a full complement of brood, stored honey, and a plan: raise a new queen, let her mate, and continue. The parent colony is diminished but functional. The swarm seeks a new home. Both halves survive, if things go well. This is the colony multiplying.

Absconding is abandonment. The entire colony departs - queen, every worker, everything. Nothing stays behind except the infrastructure: comb, honey, pollen, and sometimes brood in various stages of development. There are no queen cells left because the colony isn't planning to replace the queen. The queen is already with them. They're not splitting. They're leaving.

The distinction matters because the causes, the meaning, and the management responses are completely different. A swarm is a sign of colony strength - the colony was vigorous enough to reproduce. Absconding is a sign of colony failure - the conditions inside the hive became worse than starting over from zero.

Why Colonies Abscond

Absconding is a last resort. A colony that absconds abandons its comb - the third body of the colony, built at tremendous metabolic cost. It abandons stored honey and bee bread - weeks of foraging effort. It abandons developing brood - the next generation, already invested in but not yet returned. The cost of absconding is enormous. For European bees, the cost is usually fatal - a colony that absconds in temperate North America rarely survives to establish a new home and build up enough stores for winter.

The triggers that overcome this cost are severe.

Varroa overload. When mite levels reach the point where a significant fraction of emerging bees have deformed wings and the colony's adult population is declining faster than new bees emerge, the colony is in a death spiral. Some colonies die in place. Some abscond first - a last-ditch attempt to leave the mite-infested comb behind. The mites go with them (they're on the bees, not in the comb), so the absconding doesn't solve the mite problem. But the behavior persists because it predates Varroa - absconding evolved as a response to other comb-borne threats that could be escaped by leaving.

Small hive beetle infestation. Small hive beetles reproduce in the comb. Their larvae tunnel through comb, defecating in the honey and causing it to ferment. A colony that loses the battle against beetle larvae - when the beetle population overwhelms the bees' ability to corral and control them - faces comb that is literally rotting under its feet. The fermenting honey slimes the surfaces. The smell is distinctive and revolting. European bees sometimes abscond rather than stay in a beetle-slimed hive. African bees abscond readily at much lower beetle thresholds.

Pesticide exposure. A colony whose foragers are bringing back contaminated nectar or pollen may experience sub-lethal effects that progressively degrade hive conditions - disoriented bees, declining population, reduced brood care. If the contamination is severe enough, the colony may abscond. The mechanism isn't clearly understood - whether the bees "detect" the contamination and choose to leave, or whether the colony's condition deteriorates to the point where absconding is triggered by other cues (declining population, failing brood).

Excessive disturbance. Repeated hive inspections, vibration from nearby machinery, animal harassment (skunks scratching at the entrance nightly, bears testing the hive), and vandalism can trigger absconding. The threshold varies by genetics - some races are more tolerant of disturbance than others. But any colony repeatedly stressed by external disruption may reach the point where leaving seems preferable to staying.

Thermal stress. A hive in full sun in southern Arizona at 115 degrees Fahrenheit may exceed the colony's ability to cool itself through fanning and water evaporation. The brood nest approaches lethal temperatures. The wax softens. The comb may collapse. Absconding from a thermally uninhabitable hive is documented in hot climates.

Wax moth infestation. Wax moths in a weakened colony destroy comb from the inside, tunneling through the wax and leaving silk webbing that entangles bees. A colony overwhelmed by wax moth larvae - which only happens if the colony is already too weak to patrol and defend its comb - may abscond from the wrecked infrastructure.

The African Difference

African-lineage honey bees - Apis mellifera scutellata and the various Africanized hybrid populations in the Americas - abscond readily. In their native range in sub-Saharan Africa, absconding is a routine survival strategy, not a last resort.

The ecological context explains why. African bees evolved in an environment with a different predator profile (honey badgers, humans, driver ants), a different disease profile, and a different climate pattern than European bees. Seasonal dearths in tropical and subtropical Africa can be severe but predictable. An African colony that exhausts the local nectar flow can abscond, fly to a new location, and find blooming plants a few miles away. The year-round warm climate means there's no winter to survive - no pressure to build up massive honey stores in a permanent location.

European bees, by contrast, evolved in temperate climates where winter is coming. A colony that abandons its hive in August and starts over in a new cavity has zero chance of building enough comb, raising enough bees, and storing enough honey to survive a Minnesota winter. The evolutionary pressure on European bees is to stay put, tolerate deteriorating conditions, and die in place rather than abscond to certain death. This is why European bee absconding is rare and dramatic - the conditions have to be worse than death-by-staying for the behavior to trigger.

The difference in absconding tendency is one of the reasons Africanized bees are difficult to manage with European beekeeping methods. A Langstroth hive designed for a bee that stays put and builds up stores doesn't work for a bee whose instinct, when conditions deteriorate, is to leave and try somewhere else. Africanized colonies abscond from managed hives at rates that make commercial beekeeping impractical in some areas.

Colony Collapse Disorder Revisited

When Colony Collapse Disorder was first described in 2006-2007, the defining symptom was exactly what absconding produces: empty hives with no dead bees. Honey still in the frames. Brood abandoned. The queen gone. The similarity between CCD presentation and absconding led to early speculation that CCD was mass absconding - colonies leaving their hives in response to some stressor.

The distinction: in classic absconding, the colony relocates as a unit and can sometimes be found establishing in a new location (a tree hollow, a building cavity, another beekeeper's empty equipment). In CCD, the bees were never found. They didn't relocate. They simply failed to return - foragers left on foraging trips and never came back, depleting the colony until only the queen and a handful of young bees remained.

The current understanding is that CCD involves multiple interacting factors - Varroa, viruses (particularly deformed wing virus and Israeli acute paralysis virus), pesticide exposure, nutritional stress, and migratory stress - that collectively disorient and debilitate foragers. The empty hive isn't the result of a decision to leave. It's the result of attrition - bees leaving normally on foraging flights and failing to navigate home.

Absconding and CCD produce the same physical evidence (empty hive) through completely different mechanisms (coordinated departure vs. progressive failure to return). The diagnostic difference: an absconding colony takes its honey. A CCD-affected colony leaves its honey behind because the bees didn't plan to leave - they just didn't come back.

The Empty Hive

A beekeeper who finds an empty hive in the apiary faces a diagnostic puzzle. The colony is gone. The first question is: what happened?

If queen cells are present and some bees remain: the colony swarmed. This is normal. The remaining bees will raise a new queen from the capped queen cells. Management response: check back in 3 weeks to confirm the new queen is mated and laying.

If no queen cells, no bees, honey still present, brood abandoned: the colony absconded or experienced CCD-type population collapse. Management response: inspect the comb for signs of the trigger. Heavy Varroa - mite feces visible on cell walls, damaged pupae. Beetle damage - fermented, slimy comb. Wax moth damage - webbing, tunnels. Pesticide - look for dead bees in front of the hive (may have been cleared away), check neighboring fields for spray schedules.

If no bees, no honey, comb destroyed: the colony died (from any cause) and the resources were robbed by neighboring colonies and consumed by wax moths and beetles. This looks like absconding but is actually post-mortem cleanup by the ecosystem. The timeline tells the story: a colony that died 2 months ago looks very different from one that absconded yesterday.

The Recovery Problem

An absconded colony - the actual bees, wherever they went - faces poor odds. They left with whatever honey they could carry in their crops (roughly 40 milligrams per bee, or about 2 to 4 pounds total for a moderate colony). They need to find a suitable cavity, build comb from scratch, begin raising brood, and store enough resources to sustain themselves. In tropical and subtropical environments where African bees evolved, this is feasible year-round. In temperate climates, it's feasible only during peak nectar flow (May through July in most of the US). An absconding event in August or September in a temperate climate is a death sentence.

Beekeepers occasionally capture absconding colonies in transit - a cluster of bees on a fence post or branch that turns out to be an entire colony rather than a reproductive swarm. The giveaway is timing: reproductive swarms happen in spring and early summer. A "swarm" in September is almost certainly an absconding colony. These colonies can be hived, but they need feeding and management to build up, and they're often already weakened by whatever caused the absconding.

The Message

Absconding is the colony's final opinion about its living conditions. The fact that European bees almost never do it makes it more significant when they do. A colony that tolerates Varroa overload, beetle pressure, nutritional stress, and repeated disturbance for months before finally leaving has exhausted every other coping mechanism first. Absconding is what happens after hygienic behavior fails, after thermoregulation fails, after defense fails, after everything else the colony can do has been tried and found insufficient.

The empty hive is a post-mortem report. The bees are gone, but the evidence of why they left is still there - in the condition of the comb, the residue on the bottom board, the pattern of what was abandoned and what was taken. A beekeeper who reads that evidence learns what went wrong. A beekeeper who blames "absconding" without reading the evidence misses the lesson.

The bees left a message. They left it in wax and honey and abandoned brood. The message is always the same: this place became worse than nowhere. Fix whatever made it that way before you put another colony in the box.