Careful observation at the hive entrance provides a great deal of information about the activity inside the hive. If the beekeeper takes the trouble to compare the landing boards of several hives, they will quickly notice whether “something abnormal” is happening in front of one of their hives.

1. During winter

During winter, a weekly or biweekly check of the apiary makes it possible to ensure that the hives are stable on their stand and that the hive entrance remains permeable (► Overwintering a colony ; ► Successful overwintering).

		More or less compact snow may accumulate in front of the entrance grid; the bodies of bees that have died naturally may build up against the inner face of the grid and prevent any workers from leaving. Cleaning the entrance is necessary to ensure proper ventilation/oxygenation of the hive and to allow the colony to fly.           At the time of overwintering a colony may contain 30'000 bees; when it emerges from winter it will have only 15'000 - 20'000 bees. It is therefore possible to find a significant number of bodies each day (up to 50) at the entrance, on the landing board, or on the snow layer in front of the hive. By contrast, a very large number of bodies on the landing board of a single hive should raise suspicion of a situation that needs to be checked (starvation, thermoregulation problem, disease…). A few dead bees in the snow is normal.
Photo 1: More or less compact snow may accumulate in front of the entrance grid. As long as the snow is powdery, it remains permeable to air and the bees’ breathing is not seriously hindered. But as soon as it begins to melt and threatens to freeze at night, it may obstruct the entrance and it is recommended to remove it. Photo 2 a & b: The bodies of dead bees may accumulate against the inner face of the grid and prevent any workers from leaving. A few dead bees in the snow is normal. This occurs especially in well-populated hives and there is no reason to worry.

Regular checks of the apiary help to detect possible damage caused by woodpeckers, which tear and sometimes perforate the entire thickness of the hive wall while searching for food. Not only is the colony disturbed and its “fuel” consumption increases (stress), but workers that venture in front of the entrance grid are swallowed without hesitation. Polystyrene hives do not withstand the birds’ assaults for long, including those by tits.

Photo 3 & 4: Woodpeckers sometimes perforate the entire thickness of the hive wall while searching for food

When the temperature drops, the colony protects itself from the cold by forming a very well-structured winter cluster with an insulating outer mantle, an intermediate breathing layer and a heat-producing centre whose fuel consumption is optimized to ensure the bees’ survival. This cluster is silent : it is difficult to hear even a faint rustling when the hive is tapped…

		If a rustling is spontaneously audible during a prolonged cold spell, the cluster is probably not formed: either brood is being reared, or the colony is stressed and perhaps queenless and should be checked (intruder, mouse…).
Photo 5 : On a calm day, listen at the entrance of a strongly populated hive. More than one person will hear nothing at all. In this case, using the listening tube, one can easily assess how much they are disturbed in their winter rest.

When the temperature rises, the winter cluster breaks up; however, if it drops quickly, the bees tighten their cluster. The rustling that is perceived comes from these movements. In both cases, it is difficult to observe an increase in respiratory activity. An experienced beekeeper never welcomes a sudden change in temperature in winter, any more than a sharp day–night change, because it always leads to higher food consumption.

The presence of a little condensation water on the landing board, directly in front of the entrance, means that the colony is generating warm, humid air and is therefore clearly alive.

		The presence of a little condensation water on the landing board, directly in front of the entrance, means that the colony is generating warm, humid air and is therefore clearly alive.
Photo 6 : When nights are still cold, condensation water on the landing board often indicates the beginning of egg-laying.

 

After a long period of confinement (cold, precipitation…), bees take advantage of the first fine day to perform their cleansing flight. Older bees that have remained inside the hive for a long time and young bees that have never yet flown out carry out this cleansing flight while combining it with an orientation flight, therefore never very far from the hive entrance. Colonies that rear brood during a period of confinement produce substantial volumes of water by metabolizing honey reserves. Nurse bees store part of this undesirable water in their intestine to control humidity inside the hive and prevent the appearance of mould.

		As soon as conditions for cleansing flights are present, bees with distended intestines rush outside to relieve themselves as quickly as possible. This is why a few brownish streaks of droppings are sometimes visible on the landing board, on the hive walls, or on nearby surfaces (car bodywork, laundry on a drying rack…).
Photo 7: After winter, cleaning flights take place in early spring, during which the full fecal bladders of winter bees are emptied. In May, droppings are sprayed when young bees have received too much pollen and too little water. Splashes of black droppings may indicate the presence of nosemosis. One can also distinguish dotted tips and coherent droppings traces resembling sausages.

 

By contrast, if the hive entrance is smeared with quantities of foul-smelling droppings, with sticky bee corpses on the landing board and in front of the hive, a dysenteric disease (nosemosis) is likely. This situation occurs more often after a long period of confinement, when temperatures are cool and humidity inside the hive is too high. The bees’ distended intestine favours multiplication of the parasite Nosema apis as soon as temperatures rise somewhat during February. Conversely, in periods of poor weather conditions at the end of the season, Nosema ceranae may proliferate and cause dysentery. Finding bees fallen to the ground in front of the hive or clustering in small groups unable to fly should suggest nosemosis (► Diarrhoeal diseases).

Opening the hive confirms extensive soiling on the top bars, on the combs, on the inner surfaces of the hive, on the screened bottom, and the presence of heaps of corpses. This colony has little chance of survival and must be treated, or even destroyed, as quickly as possible to avoid contagion to an entire apiary. Frames will be discarded and the hive flamed with a blowtorch.

		Prevention: Eliminate weak colonies Keep colonies confined to a small volume Combine small healthy colonies Renew frames regularly Ensure the cleanliness of watering points and do not place them in the bees’ flight path Focus breeding on healthy, disease-resistant colonies Choose a dry, sheltered, warm site with good nectar flow conditions (including pollen supply in spring) Avoid large honeydew reserves during overwintering Guarantee the bees’ winter rest
Photo 8 & 9: After a long period of confinement, the bees’ distended intestine favours multiplication of the parasite Nosema apis as soon as temperatures rise somewhat during February. Conversely, in periods of poor weather conditions at the end of the season, Nosema ceranae may proliferate and cause dysentery.

Control:

• Prevention is the best control – there is no authorized veterinary medicinal product.
• In the case of light infestation, the best solution is to make an artificial swarm placed in a clean hive on wax foundation frames (► quick reference Emergency treatment 1.7.1. and 1.7.2. on www.abeilles.ch/varroa).
• In the case of heavy infestation, eliminating the colony and the frames is the best solution.

		If these bees hold their wings widely open in a cross (K) shape, it may be tracheal mite disease (acariosis) due to infestation by the parasite Acarapis woodi, located in the thoracic tracheae and causing lesions of the flight muscles (hence the K-wing paralysis). The bees can no longer fly. Low to moderate infestations are generally not very dangerous for the colony, but there is always a risk that the parasitosis may increase. As colonies rarely experience a winter without stress, they risk dying from cold. Infested queens may live and continue laying, but their colony may die. If 20% to 30% of the bees are affected, the colony is doomed and must be destroyed. There is no authorized treatment. Only prevention—by avoiding the acquisition of colonies of doubtful origin—can be considered.
Photo 10 -11: Signs of infestation by the parasite Acarapis woodi: adult worker honey bee exhibiting K-wing. Note how the hind wing is separated from the forewing, causing the hind wing to protrude from the thorax at a 90° angle, giving the wings and body a distinctive “K” appearance. (Credit: Honey Bee Research and Education Laboratory (honeybee@ifas.ufl.edu), University of Florida)

 

If, after a long confinement, a colony does not perform its cleansing flight like its neighbours, various hypotheses should be considered :

• The colony has not yet started rearing brood; the queen may belong to a slightly later line.
• The colony may have been robbed as early as autumn and is collapsing.
• It cannot leave because the entrance is blocked by corpses or other debris deposited by an intruder (mouse).
• The colony may have died of hunger and cold because it was overwintered on too many frames, too far from the food.

If the cause of the absence of cleansing flights is not clear, one should take advantage of the next fine day to open the hive carefully and look for open brood (evidence of the queen’s presence) or confirm that the colony is dead (discard frames, sterilize the hive with a blowtorch).

Photo 12: From late January/early February, the queen resumes egg-laying and foragers bring in hazel pollen

From late January/early February, the queen resumes egg-laying, foragers bring in hazel pollen followed by willow pollen, and water carriers are working at full capacity for the production of royal jelly by nurse bees. An elegant way to check the water needs of brood-rearing colonies is to place a reference watering point near the hives. The constant dance of water carriers and the pollen inflow confirm brood rearing. 

Photo 13: By late March, the arrival of shapeless, grey or greenish pellets during the pre-flowering of birch/poplar/chestnut confirms that foragers are collecting their first propolis to ensure hygiene inside the hive (► Propolis).

 

2. In spring

In spring, colony activity accelerates and fuel consumption skyrockets to keep brood temperature above 34°C. Pollen and nectar/honey consumption follows the development of the open brood area (► All about feeding).

 

		If bees deposit white, shiny sugar crystals on the landing board, they have begun to devour reserves from the outer frames and it is time to offer 50% syrup to prevent the onset of May disease (► May disease). Nurse bees that do not have enough water available can no longer digest pollen to produce royal jelly. They fall in small trembling clusters in front of the hive.
Photo 14: White, shiny sugar crystals on the landing board may indicate a lack of water. Photo 15: The presence of many yellowish droppings filaments catches the beekeeper’s attention.

The presence of yellowish droppings filaments on the landing board catches the beekeeper’s attention. By applying pressure to their completely full abdomen, a thick yellow to brownish dropping is expelled. Water must quickly be sprayed onto the bees between the frames, or water must be provided via a supplementary feeder (diluted sweetened lukewarm water at 50% or pure water if the super is already in place (► What water for our bees).

 

		Finding white pupae on the morning after a cold night means that part of the brood could not be kept warm by too few workers and that this chilled brood is removed from the hive to avoid bacterial superinfection. Lizards and birds will take advantage as well…
Photo 16a & b: Finding white pupae on the morning after a cold night may indicate that part of the brood could not be kept warm by too few workers (► Sense and nonsense of thermal insulation of hives).

The presence of a large amount of condensation water in the morning in front of the entrance confirms the good health of a colony that is rearing a large brood. Large inflows of multicoloured pollen confirm the colony’s vitality .

Photo 17: If bees bring in a lot of pollen, it is a good sign (► Recognizing pollen).

It is always useful to compare the activity of several hives in the same apiary to confirm regular colony development. A colony that brings in little or no pollen and whose forager traffic is clearly sparse compared with adjacent hives should attract the beekeeper’s attention. A more thorough inspection is required to clarify the cause of this delay. It should be remembered that a colony kept tight in spring will develop more rapidly than a colony occupying too large a volume that is difficult to heat.

On a fine afternoon with mild temperatures, one can observe in front of several hives dense flights radiating in all directions, with groups of bees on the front, just above the entrance. These seemingly disordered flights correspond to orientation flights by young bees that survey the surroundings of their hive in preparation for their future work as foragers. They perform increasingly distant trajectories to memorize the foraging area and landmarks to return home. It is like fireworks. These flights are entirely different from swarming. When a swarm leaves the hive, one witnesses a true “flow” of bees out of the hive, of very short duration—on the order of a minute—and the sound resembles a buzzing. The swarm flight is more or less compact and settles within about 10 minutes not far from the hive to form a pear-shaped cluster hanging from the branch, at a more or less elevated height, of a nearby tree.

Photo 18: Orientation flights by young bees surveying the surroundings of their hive often take place in the afternoon between 14h00 - 16h00 and should not be confused with swarming (often between 11h00 - 14h00).

In the morning, one may find a small white caterpillar on the landing board. Wax moth larvae readily feed on wax and pollen debris found on the hive floor (► The wax moth).

		Bees tolerate adult moths and are unable to dislodge pupae buried in their cocoons. By contrast, larvae moving more slowly on the combs are actively hunted and expelled from the hive, to the great delight of passerine birds.
Photo 19: Wax moth larvae readily feed on wax and pollen debris found on the hive floor.

In the morning one may discover whitish, grey, or black concretions on the hive floor and the landing board, most often in spring due to cold snaps and poor nutritional intake. Chalkbrood (plastered; ascosphaerosis) is a fungal disease affecting worker and drone brood. Contamination of larvae by fungal spores leads to their death, desiccation, and the formation of mummies. 

Stonebrood (aspergillosis larvae apium) is a fungal disease caused by species of fungi in the genus Aspergillus : A. fumigatus, A. flavus, and A. niger. It causes the mummification of brood in a honeybee colony. These fungi are common in soils and are also pathogenic to other insects, birds, and mammals. The disease is difficult to identify in the early stages of infection. Spores of different species have different colours and can also cause respiratory disorders in humans and other animals. When bee larvae ingest spores, they can hatch in the intestine and develop rapidly to form a collar-like ring near the larval heads. After death, larvae turn black and are difficult to crush, hence the name stonebrood. Eventually, the fungus emerges from the larval cuticle and forms a false skin. At this stage, larvae are covered with powdery fungal spores. Worker bees clean the infected brood and the hive can recover depending on factors such as colony strength, the level of infection, and the hygienic habits of the bee strain (this trait varies among different subspecies).

		Ascosphaera apis causes a fungal disease that infects the larvae’s intestine. The fungus competes with them for food, causing them to starve. The fungus then continues consuming the remaining larval bodies, making them appear white and “chalky”.    If the colony is not too severely affected, providing protein in the form of pollen and 50% syrup can solve the problem. Sometimes replacing the infected queen is necessary. If the colony is severely affected, creating an artificial swarm is required, or even sulphuring the colony to avoid contamination of an entire apiary (► Chalkbrood)
Photo 20 - 22: Chalkbrood (plastered; ascosphaerosis larvae apium) is most often visible during wet springs. Chalkbrood hives can generally be recovered by increasing ventilation in the hive.

 

		During a nectar flow, bees may appear clustered at the entrance, disrupting take-off and landing of foragers, and many pollen pellets may carpet the landing board. The hive entrance is certainly too narrow and the grids should be spread to improve traffic flow
Photo 23: If the entrance is too small, there may be traffic jams.  Ventilating bees clog it and bees leaving block the paths of those returning heavily loaded. Over time, these time losses translate into reduced harvest. Nevertheless, an opening that is too large promotes robbing.

If all activity suddenly ceases in a strong colony, swarming has been decided. The colony has built queen cells in which the queen has laid eggs and which may already contain queen larvae. These cells will soon be capped. If one wants to prevent swarming, an artificial swarm must be taken without hesitation.

Photo 23a: If all activity suddenly ceases in a strong colony, swarming is imminent. This colony will swarm very shortly, perhaps within a few minutes. A prime swarm leaves the hive as soon as the first queen cell is capped. If it rains at that moment or if the temperature is not suitable, it then waits for the first fine day. In a prime swarm, the queen almost always appears last.

Between 10 h and 11 h, suddenly you hear the flight of drones, which is unusual at that time, and you quickly identify the colony they come from. It is flying irregularly and pollen-laden bees are leaving the entrance. 

When you walk slowly in front of the apiary in the evening, as the sounds of the day gradually fade, you can hear very distinctly the “tut ” of a young queen through the entrance of populations that have produced a prime swarm. The “qwak” of queens still in the cells is more difficult to hear. This colony will produce, the next day or at the latest on the 3rd day, a secondary swarm. In the secondary swarm as in the “singing swarm”, the queen appears first. Both leave even if the temperature is less favourable and both build exclusively worker cells for 3 weeks.

A colony that has not produced a prime swarm gives the well-known “tut”. The queen of this colony died about two weeks ago or was injured or killed during an inspection, which often happens. This colony produces the next day a “singing swarm” (► Swarming).

 

3. In summer

In summer, when the internal temperature of the hive is too high, a large part of the colony leaves it, instinctively sensing various dangers (softening of comb structures, collapse of combs loaded with honey or brood). If the temperature continues to rise above 36 °C, the brood suffers and may die. This dead brood decomposes in the cells, but it must not be confused with foulbrood. Ventilation must be provided immediately and the tray removed if it is in place. This situation occurs most often in apiaries exposed to the south and lacking any protection from the sun’s rays striking the hive entrance directly.

		When the outside temperature rises above 30°C, one can observe a more or less voluminous cluster of bees hanging at the end of the landing board. They “beard” to reduce the load on wax combs that threaten to soften and collapse along with brood and stores.
Photo 24: In summer when it is very hot, a cluster of bees in front of the entrance is nothing to worry about unless the temperature continues to rise above 36 °C.

Other workers, the “ventilators”, brace themselves on the landing board with their head facing the hive entrance, their body flat and wings beating vigorously. The airflow produced evaporates the water brought by the “air conditioners” and lowers the temperature in the brood chamber. The same phenomenon is observed when bees seek to reduce the moisture content of honey, just before capping and then storing. 

 

Photo 25: In summer, when the outside temperature is high, the “air conditioners” lower the temperature in the brood chamber.

 

		This thermoregulation should not be confused with bees fanning the “call” after hiving a recovered swarm or during orientation flights.
Photo 26: The Nasonov pheromone is released by worker bees to orient foragers returning to the colony. To diffuse this odour, bees raise their abdomen, which contains the Nasonov glands, and beat their wings vigorously.

Bees are clustered in front of the entrance, facing the hive, wings beating, but the tip of their abdomen is pointed upward and one can see a separation of the last abdominal segment allowing dissemination of the trail pheromone produced by the Nasonov gland (► Royal pheromones).

4. In autumn

In autumn, colonies prepare for overwintering. This is a period of profound behavioural reorganization within the colony. Drones have become useless mouths and workers starve them before expelling them from the hive without mercy or hesitation. 

 

		If drones are expelled, it is a sign that a queen is present in the hive. This is the ideal time to replace the queen if she is more than 3 years old.
Photo 27 & 28: Expulsion of drones. Every colony with a queen expels its drones in August. Some time beforehand, bees stop feeding these useless mouths in order to weaken them.

After a night colder than usual, one may observe larvae or white pupae on the landing board in the morning. For the same reasons already mentioned in spring, chilled brood is removed and expelled from the hive by cleaning bees.

Observing the landing board sometimes reveals workers unable to fly, with deformed and atrophied wings. These bees were victims during their pupal stage of the DWV virus transmitted by varroa. This is a dreaded warning sign, as varroa pressure may cause colony collapse even before winter arrives. A check of natural mite fall on the tray and treatment are required if the fall exceeds 5/day  (► Deformed wing disease) !

Photo 29: The deformed wing virus or DWV (Deformed wing virus) is an RNA virus that affects honeybees. Affected individuals show severely shrunken wings as a symptom, preventing the bee from flying. (Source: KnackBockBlog | Seite 14 , wordpress.com) (► Resistance to varroa).

In autumn, the colony has one priority objective : to store food reserves for winter. Observing chaotic activity with fighting in front of a hive entrance, with clusters of bees under the tray, in gaps at the roof or feeder, the presence of black, hairless bees (they have lost their hairs in the scuffle), granular and sticky deposits in front of the entrance and on the metal grid makes it possible to recognize robbing without hesitation. Sometimes robbing is carried out by wasps: the scene is very discreet, but the incessant comings and goings of these hymenopterans, close cousins, draw heavily on the colony’s reserves without really triggering defence by the guards. The favouring factor is the presence or smell of honey or syrup in the apiary. Be careful when feeding with concentrated syrup and even more so with 50% syrup: the slightest drop spilled on the ground attracts foragers and soon frenzy takes hold of the whole apiary. To avoid agitation, feed preferably in the evening when foragers are inside the hive. Similarly, letting supers’ frames be licked after extraction is risky.

		Robbing implies robbers and robbed colonies. A weak hive whose guards cannot effectively defend the entrance will fall prey to a strong colony that seizes its food stores… but also the likely numerous varroa that take advantage of immune decline to multiply and spread their share of viruses ! Robbing is therefore a double-edged sword. The only real beneficiary is phoretic varroa, which can change “roof” and spread throughout the apiary despite two summer treatments ! A robbed hive must therefore be closed and moved away from the apiary to avoid fuelling robbing fever and disease transmission. The survival of this colony is uncertain even before overwintering. It should be remembered that robbing of a colony is not a disease in itself but the consequence of a progressive collapse of a colony that is failing for x reasons. In recent years, some beekeepers have become concerned to see their hives more regularly and more strongly attacked by the Asian hornet. Hovering about twenty centimetres from the hive entrance, a Vespa velutina nigrithorax worker regularly replaces another to capture foragers returning to the hive loaded with pollen. The hornet darts at its prey, grabs it between its legs and kills it with a single mandible bite behind the head before carrying it into a tree to dismember it.
Photo 30 - 32: The danger of robbing is even greater in August than in April. Many foragers try to bring food back this way before dying. The entrance must be narrowed in time. Robbers are astonishingly tenacious. Robbing by wasps is less spectacular but effective (► The Asian hornet is arriving in Switzerland). .

Anecdote: on a day of strong nectar flow, intense traffic takes place between the landing boards of two neighbouring colonies; it runs along the hive fronts but may also take more circuitous routes. This is an indication of latent robbing. One colony robs another in the most civil manner. A screen placed between the hives is most often crossed or bypassed. Robbers even enter the hive. This latent robbing sometimes explains abnormally high yields.

Conclusion:

Each season offers the curious beekeeper scenes that must be interpreted correctly to infer what is happening inside the hive. By combining these entrance observations with reading the tray (► The fascinating secrets of reading debris), a true mirror of life beneath the frames, one can refine one’s hypotheses. If the cover is made of transparent PVC (plexiglass), observing colony activity from above allows a quick assessment of colony development. The ultimate remains the connected hive (► Real-time observations)