{"id":25095165,"date":"2026-09-10T19:44:28","date_gmt":"2026-09-10T17:44:28","guid":{"rendered":"https:\/\/frelons.be\/2026\/09\/10\/nid-primaire-et-secondaire-le-guide-complet-pour-les-reconnaitre\/"},"modified":"2026-09-10T19:44:28","modified_gmt":"2026-09-10T17:44:28","slug":"primary-and-secondary-nests-the-complete-guide-to-identifying-them","status":"publish","type":"post","link":"https:\/\/frelons.be\/en\/2026\/09\/10\/nid-primaire-et-secondaire-le-guide-complet-pour-les-reconnaitre\/","title":{"rendered":"Primary and Secondary Nests: The Complete Guide to Identifying Them"},"content":{"rendered":"<h1>Primary Nest or Secondary Nest: How Can You Tell the Difference?<\/h1>\n<h3 id=\"sommaire\">Contents<\/h3>\n<ul>\n<li>\n<p><a target=\"_blank\" rel=\"noopener noreferrer nofollow\" class=\"text-primary underline toc-link\" href=\"#le-nid-primaire-identifier-la-petite-sphere-printaniere-du-frelon\">The primary nest: identifying the hornet\u2019s small spring nest<\/a><\/p>\n<\/li>\n<li>\n<p><a target=\"_blank\" rel=\"noopener noreferrer nofollow\" class=\"text-primary underline toc-link\" href=\"#le-nid-secondaire-reconnaitre-la-forteresse-estivale-en-hauteur\">The Secondary Nest: Recognizing the Summer Fortress High Up in the Trees<\/a><\/p>\n<\/li>\n<li>\n<p><a target=\"_blank\" rel=\"noopener noreferrer nofollow\" class=\"text-primary underline toc-link\" href=\"#cycle-de-vie-et-transition-comment-agir-face-a-chaque-type-de-nid\">Life Cycle and Transition: How to Handle Each Type of Nest<\/a><\/p>\n<\/li>\n<li>\n<p><a target=\"_blank\" rel=\"noopener noreferrer nofollow\" class=\"text-primary underline toc-link\" href=\"#conclusion\">Conclusion<\/a><\/p>\n<\/li>\n<\/ul>\n<p>A paper ball under an awning in the spring, a large brown nest in a tree in September: these two structures may belong to the same species, the Asian hornet. The difference between them is not just a matter of size. They often correspond to two stages in the development of a colony, with the colony moving to a new location between the two.<\/p>\n<h3 id=\"ce-qu-il-faut-retenir\">Things to remember<\/h3>\n<ul>\n<li>\n<p>This teaching guide discusses the visual and temporal differences between the two types of nests<\/p>\n<\/li>\n<li>\n<p>This unique approach is based on explaining the phenomenon of transition (the move from elementary to middle school) to encourage active civic engagement throughout the year\u2014a hallmark of Frelons.<\/p>\n<\/li>\n<li>\n<p>Identify the hornet's small spring egg sac<\/p>\n<\/li>\n<li>\n<p>recognize the summer fortress high up on the hill<\/p>\n<\/li>\n<\/ul>\n<p>To distinguish between a primary nest and a secondary nest, look for three clues: <strong>shape, location, and season<\/strong>. None of these measures is sufficient on its own. Understanding this transition from one nest to another helps avoid a common mistake: believing that the hornets have disappeared simply because their small spring nest appears to have been abandoned. At Frelons.be, vigilance is a year-round commitment, with specific precautions tailored to each season.<\/p>\n<h2 id=\"le-nid-primaire-identifier-la-petite-sphere-printaniere-du-frelon\">The primary nest: identifying the hornet\u2019s small spring nest<\/h2>\n<p>Have you spotted a small beige sphere on the ceiling of your garden shed? In the spring, this discovery is worth paying attention to. The Asian hornet\u2019s primary nest is the colony\u2019s first structure. In the early stages, when a founding queen is still working alone, it is also referred to as <strong>embryonic nest<\/strong>.<\/p>\n<p>The queen builds her cocoon from chewed wood fibers mixed with her saliva. The result resembles thin paper, with shades of beige or brown. Inside, the first cells house the eggs and then the larvae. The casing usually hides these cells: there\u2019s no need to try to look inside to confirm your observation.<\/p>\n<p><img decoding=\"async\" class=\"max-w-full h-auto rounded-md\" src=\"https:\/\/nghaeknymynesecnqcmd.supabase.co\/storage\/v1\/object\/public\/article-images\/article-1788977044000-nid-primaire-et-secondaire-le-guide-complet-pour-les-reconnaitre.png\" alt=\"Primary and Secondary Nests: The Complete Guide to Identifying Them\"><\/p>\n<p>Here are the key signs to look for when identifying a nest in the spring:<\/p>\n<ul>\n<li>\n<p><strong>Size:<\/strong> A few centimeters at the very beginning\u2014often around 3 to 5 cm\u2014followed by gradual growth. A primary nest can reach about ten centimeters and sometimes even more before the birds eventually move to a new location.<\/p>\n<\/li>\n<li>\n<p><strong>The form:<\/strong> a small sphere or a slightly rounded ball, wrapped in paper.<\/p>\n<\/li>\n<li>\n<p><strong>The entrance:<\/strong> an opening that is generally located toward the bottom in the early stages. Its position may change as construction progresses.<\/p>\n<\/li>\n<li>\n<p><strong>The situation:<\/strong> a spot sheltered from rain and wind, not necessarily very high up.<\/p>\n<\/li>\n<\/ul>\n<p>Where can you look without taking any risks? Check the undersides of roofs, awnings, carports, and garden sheds from the ground. A window frame, a shutter box, or an open outbuilding can also provide a hiding place. Do not open a suspicious box or move objects to clear away the nest: a hidden colony may react to the disturbance.<\/p>\n<p>The size of the primary nest makes it impossible to count its occupants. At first, only the adult queen is responsible for construction and foraging. After the first workers emerge, several individuals\u2014and later, depending on the colony\u2019s growth, a few dozen\u2014can move about within it. <strong>Therefore, seeing just one hornet does not mean there is only one hornet present.<\/strong><\/p>\n<p>Be careful not to confuse them. The early nests of certain wasps closely resemble those of the Asian hornet. To identify a hornet nest more reliably, observing the insects can help: the yellow-legged hornet has a very dark thorax, a mostly dark abdomen marked with a broad orange band, and yellow tips on its legs. A zoomed-in photo, taken from a distance, is better than an identification based solely on the color of the paper.<\/p>\n<h2 id=\"le-nid-secondaire-reconnaitre-la-forteresse-estivale-en-hauteur\">The Secondary Nest: Recognizing the Summer Fortress High Up in the Trees<\/h2>\n<p>Over 50 cm tall, sometimes nearly a meter by the end of the season: the secondary nest grows significantly in size. This structure accompanies the expansion of the colony, whose space requirements increase as the number of workers grows and the brood develops. It often becomes visible in the summer and is much easier to spot once the leaves fall.<\/p>\n<p>The secondary nest of the Asian hornet is generally oval or pear-shaped. Its thick outer shell has distinct layers and striations in shades of grayish-brown. Unlike the small initial sphere, its entrance is <strong>often lateral<\/strong>. This detail is a good clue, but not conclusive proof: from the ground, the opening may be hidden by a branch or facing the opposite direction.<\/p>\n<p>It is frequently found in a tree\u2019s crown, several meters\u2014or even several tens of meters\u2014above the ground. The foliage can conceal what is already a large structure. Regular comings and goings around a specific spot sometimes draw attention before the nest itself does. Observing with binoculars from a distance allows you to better understand what you\u2019re seeing without having to go under the colony.<\/p>\n<p>But a nest high up is not the only possible location. A dense hedge, a bush, a building facade, or a man-made structure can also support a thriving colony. <strong>A large nest at eye level is still entirely possible<\/strong>, and it increases the risk of accidental contact, particularly while pruning or clearing brush.<\/p>\n<p>The difference between a primary and a secondary nest is therefore based on a set of criteria:<\/p>\n<ul>\n<li>\n<p><strong>In the spring:<\/strong> A small, sheltered structure is more reminiscent of the beginnings of a colony.<\/p>\n<\/li>\n<li>\n<p><strong>In the summer and fall:<\/strong> A large, often oval-shaped mass is more indicative of an advanced colony.<\/p>\n<\/li>\n<li>\n<p><strong>A low or side entrance:<\/strong> It helps with identification, without replacing the observation of hornets.<\/p>\n<\/li>\n<li>\n<p><strong>Height :<\/strong> It is common in secondary nests, but does not, on its own, define their nature.<\/p>\n<\/li>\n<\/ul>\n<p>The term \u00abpermanent nest\u00bb refers to the main dwelling occupied until the end of the annual cycle. It does not mean that the hornets will return there every year. The colony is annual, and the old nest is not normally reused the following year.<\/p>\n<p>One final point: the size of a hornet\u2019s nest does not indicate its current activity. A large nest discovered in winter may be empty, while a small spring nest may be home to an active queen. Before making any decisions, it is important to consider the season in which the nest was observed and to confirm the situation.<\/p>\n<h2 id=\"cycle-de-vie-et-transition-comment-agir-face-a-chaque-type-de-nid\">Life Cycle and Transition: How to Handle Each Type of Nest<\/h2>\n<p>The move doesn\u2019t happen overnight, with the old location disappearing immediately. Relocating the nest is a transition: when the original location becomes too restrictive, worker bees begin building a new nest, while activity may continue temporarily at the original site. The colony gradually settles into its new home.<\/p>\n<p>This phase often occurs in late spring or early summer, though the timing may vary depending on the weather and the colony\u2019s development. It does not occur every year. <strong>If the original site offers enough space and favorable conditions, the nest can be expanded on site.<\/strong> The terms \u201cprimary\u201d and \u201csecondary\u201d therefore describe a common path, not two mandatory moves scheduled on a calendar.<\/p>\n<p>Here\u2019s the key point to remember when a small nest suddenly appears to be abandoned: the colony may have failed, but it may also have moved. Do not remove this initial structure, assuming the problem is solved. Report its location, the date of your last sighting, and any hornet flight paths visible from a safe distance.<\/p>\n<p>To track the life cycle of the Asian hornet in Belgium, keep these general guidelines in mind:<\/p>\n<ul>\n<li>\n<p><strong>In the spring:<\/strong> The queen bees that survived the winter emerge from their shelters and begin the nesting period. The dates depend largely on temperatures.<\/p>\n<\/li>\n<li>\n<p><strong>From late spring through summer:<\/strong> The worker bees take over many tasks. The colony grows, with or without relocation.<\/p>\n<\/li>\n<li>\n<p><strong>In late summer and fall:<\/strong> Established colonies produce reproductive individuals, including future colony founders.<\/p>\n<\/li>\n<li>\n<p><strong>As winter approaches:<\/strong> The colony is in decline. The future fertilized queens seek shelter for the winter, usually outside the nest, while the former queen and the workers die.<\/p>\n<\/li>\n<\/ul>\n<p>What should you do if you find a hornet\u2019s nest, whether small or large? The right answer is to avoid tampering with it. Do not swat at it with a broom, spray it with water, set it on fire, use insecticide spray, or try to block the entrance. Just because a nest is accessible doesn\u2019t mean it\u2019s safe.<\/p>\n<ol>\n<li>\n<p><strong>Keep people and animals away.<\/strong> Stay several meters away\u2014and even further if the hornets react\u2014and block access to the area without getting close to the nest.<\/p>\n<\/li>\n<li>\n<p><strong>Stop any work being done nearby.<\/strong> Hedge trimmers, lawn mowers, and vibrations can trigger a defensive reaction when they disturb the colony.<\/p>\n<\/li>\n<li>\n<p><strong>Document without putting yourself at risk.<\/strong> Note the address, the structure, the approximate height, and whether there is any traffic coming and going. Take photos only from a safe location.<\/p>\n<\/li>\n<li>\n<p><strong>Have the identity confirmed.<\/strong> Contact Frelons.be or the appropriate reporting hotline in your area to be referred to the appropriate service.<\/p>\n<\/li>\n<\/ol>\n<p>The removal of an active hornet nest must be entrusted to a trained and properly equipped professional. Taking early action against a confirmed colony can prevent it from growing, but the removal must still be handled by a professional, even in the case of a nest in its early stages. If you are stung and experience difficulty breathing, dizziness, or swelling of the throat, call 112 immediately.<\/p>\n<h2 id=\"conclusion\">Conclusion<\/h2>\n<p>Keep three guidelines in mind\u2014not a rigid rule: the small, sheltered sphere suggests spring; the large, egg-shaped nest suggests a well-established colony; and the season helps give meaning to these observations. It is the combination of these features that helps distinguish between a primary nest and a secondary nest. Neither the diameter nor the height alone is sufficient to make a definitive determination.<\/p>\n<p>Your role is not to determine how many workers live inside or to inspect the entrance down to the centimeter. A useful observation consists of a few simple details: where the structure is located, when you discovered it, what shape it has, and whether insects are entering or leaving it. When shared with a qualified professional, this information makes it easier to assess the situation without putting you in danger.<\/p>\n<p>A change in location warrants special attention. A spring nest that\u2019s been abandoned doesn\u2019t prove that the colony has disappeared from the neighborhood. Conversely, seeing hornets foraging in your yard doesn\u2019t prove that there\u2019s a nest on your property. Avoid following the insects through a hedge or onto a neighbor\u2019s property: it\u2019s better to share a precise observation than to search for a colony at all costs.<\/p>\n<p><strong>It\u2019s important to remain vigilant year-round, but that doesn\u2019t mean you have to treat your plants year-round.<\/strong> In the spring, it helps identify small nests. In the summer, it helps prevent accidental encounters during outdoor work. In the fall, falling leaves reveal nests that were previously hidden. In winter, reporting a sighting allows you to document a discovery and ask whether an inspection is necessary. An old, truly inactive nest does not warrant treatment with insecticide.<\/p>\n<p>Before trimming a hedge that hasn\u2019t been touched in a long time or using a rarely used outbuilding, take the time to observe it from the outside. This simple precaution is better than an impromptu inspection from inside the branches. If you notice a large number of large insects swarming around, stop what you\u2019re doing and have the area checked.<\/p>\n<p>Do you have any concerns about a structural issue in your home? <strong>Contact Frelons.be with a photo taken from a distance and its location.<\/strong> Our approach is based on this ongoing civic vigilance: identifying colonies, understanding their stage of development, and taking action at the right time\u2014without turning a discovery into a risk.<\/p>\n<h2 id=\"questions-frequentes\">Frequently asked questions<\/h2>\n<details class=\"faq-item\">\n<summary>What clues can help distinguish a primary nest from a secondary nest?<\/summary>\n<p>Consider the shape, location, and season: a small beige paper sphere, sheltered under an overhang in the spring, is more likely to be a primary nest. A large ovoid or pear-shaped structure, often found in a tree in summer or fall, is more likely to be a secondary nest. The entrance, which is usually low at first and then often shifts to the side, provides an additional clue, but no single criterion is sufficient on its own.<\/p>\n<\/details>\n<details class=\"faq-item\">\n<summary>How can you avoid confusing a small Asian hornet nest with a wasp nest?<\/summary>\n<p>The early nests of certain wasps closely resemble those of the Asian hornet; therefore, the color of the paper and the size alone are not enough to tell them apart. Observing the insects provides more insight: the Asian hornet has a very dark thorax, a broad orange band on a mostly dark abdomen, and yellow tips on its legs. Take a zoomed-in photo from a distance to confirm the identification, without trying to look inside the nest.<\/p>\n<\/details>\n<details class=\"faq-item\">\n<summary>Does a primary nest that appears to be abandoned mean that the hornets have left?<\/summary>\n<p>Not necessarily: the colony may have failed, but it may also have begun settling into a secondary nest, often in late spring or early summer. This move is gradual, with activity sometimes continuing temporarily at both locations, and it doesn\u2019t always happen if the first site allows for expansion. Do not remove the nest: note its location, the date of your last sighting, and the flight paths visible from a safe distance.<\/p>\n<\/details>\n<details class=\"faq-item\">\n<summary>Can a large nest in a hedge be a secondary nest?<\/summary>\n<p>Yes, a secondary nest isn\u2019t necessarily perched at the top of a tree: a dense hedge, a bush, a building facade, or a man-made structure can also harbor a well-established colony. At eye level, the risk of accidental contact increases, particularly during pruning or brush clearing. If you notice a concentrated swarm of large insects, stop working and have the area inspected without exploring the branches.<\/p>\n<\/details>\n<details class=\"faq-item\">\n<summary>Can I remove a small, easily accessible primary nest on my own?<\/summary>\n<p>No: Even an embryonic nest must be handled by a trained and properly equipped professional, because its small size does not guarantee that it contains only one occupant or that it poses no danger. Do not touch it, do not block its entrance, and do not use a water spray or insecticide. Keep people and animals away, stop any work being done nearby, and contact Frelons.be or the appropriate regional authority, providing the location and, if possible, a photo taken from a distance.<\/p>\n<\/details>\n<details class=\"faq-item\">\n<summary>Should you have a large nest that was discovered in winter treated?<\/summary>\n<p>Not automatically: a large structure discovered in the winter may be empty, and a former nest that is truly inactive does not warrant treatment with insecticide. The colony is annual; future queens typically overwinter elsewhere, and the old nest is not normally reused the following year. Reporting the discovery helps document it and determine whether an inspection is necessary, without assuming activity based solely on the nest\u2019s size.<\/p>\n<\/details>","protected":false},"excerpt":{"rendered":"<p>Primary Nest or Secondary Nest: How to Tell Them Apart? Table of Contents The Primary Nest: Identifying the Hornet\u2019s Small Spring Nest The Secondary Nest: Recognizing the Summer Fortress High Up Cy\u2026<\/p>","protected":false},"author":2,"featured_media":25095164,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-25095165","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-non-classe"],"_links":{"self":[{"href":"https:\/\/frelons.be\/en\/wp-json\/wp\/v2\/posts\/25095165","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/frelons.be\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/frelons.be\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/frelons.be\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/frelons.be\/en\/wp-json\/wp\/v2\/comments?post=25095165"}],"version-history":[{"count":0,"href":"https:\/\/frelons.be\/en\/wp-json\/wp\/v2\/posts\/25095165\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/frelons.be\/en\/wp-json\/wp\/v2\/media\/25095164"}],"wp:attachment":[{"href":"https:\/\/frelons.be\/en\/wp-json\/wp\/v2\/media?parent=25095165"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/frelons.be\/en\/wp-json\/wp\/v2\/categories?post=25095165"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/frelons.be\/en\/wp-json\/wp\/v2\/tags?post=25095165"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}