Ever wondered how birds manage to fly thousands of kilometers without ever stopping to ask for directions? No Google Maps, no compass, no ‘turn left at the next cloud’ – and yet they never get lost. Let’s explore the mind-blowing ways these feathered travelers find their way across the planet.
每年，数十亿只鸟在地球上进行长途迁徙。北极燕鸥从北极飞到南极，单程超过七万公里。黑脉金斑蝶从加拿大飞到墨西哥，穿越整个北美大陆。这些动物没有地图，没有手机，没有任何现代导航工具。那么，它们是怎么找到方向的？科学家经过多年研究，发现鸟类拥有多种令人惊叹的导航系统。
首先，许多鸟类可以感应地球的磁场。地球本身就是一个巨大的磁铁，从南极到北极都有磁力线。科学家发现，鸟类的眼睛和喙部含有一种特殊的物质，可以感知磁场的方向和强度。这就像是鸟类天生就有一个内置的指南针，无论飞到哪里，都能感知自己相对于磁极的位置。研究人员曾经用人工磁场干扰鸟类的迁徙，结果发现鸟类的飞行方向出现了明显的偏差，从而证明了磁场感应的存在。
其次，鸟类也会利用太阳和星星来导航。白天，它们根据太阳的位置判断方向，同时利用体内的生物钟来计算时间，从而确定太阳在一天中不同时间应该在天空中的哪个位置。晚上，许多鸟类依靠星星导航，尤其是北极星附近的星座。科学家做过实验，把鸟放在人工星空下，改变星座的位置，结果鸟类的飞行方向也跟着改变了。
除此之外，鸟类还会利用地形、气味、声音，甚至次声波来帮助导航。它们能够记住山脉、河流和海岸线的形状，就像人类记住熟悉的街道一样。有些鸟类甚至可以通过闻气味来判断自己的位置——鸽子就被发现可以通过空气中不同地区的气味来确定方向。
最令人惊讶的是，这些导航能力有些是天生的，有些是后天学习的。年轻的鸟类在第一次迁徙时，会跟随年长的鸟类飞行，在飞行过程中学习路线。但是即使是第一次单独迁徙的幼鸟，也能大致找到正确的方向，说明部分导航能力是写在基因里的。
鸟类的导航系统提醒我们，大自然的智慧远比我们想象的复杂。我们花了几千年才发明出指南针和GPS，而鸟类在数百万年前就已经拥有了比这更精妙的导航系统。也许，我们对自然界的了解，还远远不够。
Hover a word for its pinyin & meaning; click to pin it.
| Word | Pinyin | Meaning |
|---|---|---|
| 迁徙 | qiānxǐ | migration |
| 磁场 | cíchǎng | magnetic field |
| 导航 | dǎoháng | navigation |
| 指南针 | zhǐnánzhēn | compass |
| 生物钟 | shēngwùzhōng | biological clock |
| 星座 | xīngzuò | constellation |
| 次声波 | cìshēngbō | infrasound |
| 基因 | jīyīn | gene |
| 感应 | gǎnyìng | to sense/detect |
| 每年 | měi nián | every year; each year; yearly |
| 数 | shǔ | to count; to count as; to regard as; to enumerate; to list |
| 十 | shí | ten; 10 |
| 亿 | yì | 100 million |
| 只 | zhī | variant of 隻|只[zhi1]; variant of 只[zhi3]; grain that has begun to ripen; classifier for birds and certain animals, one of a pair, some utensils, vessels etc |
| 鸟 | diǎo | variant of 屌[diao3]; penis |
| 在 | zài | to exist; to be alive; (of sb or sth) to be (located) at; (used before a verb to indicate an action in progress) |
| 地球 | dì qíu | the earth |
| 上进 | shàng jìn | to make progress; to do better; fig. ambitious to improve oneself; to move forwards |
| 行长 | háng zhǎng | bank president |
| 途 | tū | way; road |
| 北 | běi | north; (classical) to be defeated |
| 极 | jí | extremely; pole (geography, physics); utmost; top |
| 燕 | Yān | Yan, a vassal state of Zhou in present-day Hebei and Liaoning; north Hebei; the four Yan kingdoms of the Sixteen Kingdoms, namely: Former Yan 前燕[Qian2 Yan1] (337–370), Later Yan 後燕…; variant of 燕[yan4] |
| 鸥 | ōu | common gull |
| 从 | cóng | variant of 從|从[cong2]; surname Cong |
| 飞 | fēi | to fly |
| 到 | dào | to reach; to arrive; to leave for; to go to; to (a place); until (a time); up to (a point); (verb complement indicating arriving at a place or reaching a point); considerate; thoug… |
| 南 | Nán | surname Nan |
| 单程 | dān chéng | one-way (ticket) |
| 超 | chao | to exceed; to surpass; to pass; ultra- |
| 过 | Guō | surname Guo |
| 七 | qī | seven; 7 |
| 万 | mò | used in 万俟[Mo4 qi2]; surname Wan |
| 公里 | gōng lǐ | kilometer |
| 黑 | Hēi | short name for Heilongjiang 黑龍江|黑龙江[Hei1 long2 jiang1] |
| 脉 | mǎi | old |
| 金 | Jīn | surname Jin; surname Kim (Korean); Jurchen Jin dynasty (1115–1234) |
| 斑 | bān | spot; colored patch; stripe; spotted; striped; variegated |
| 蝶 | dié | variant of 蝶[die2]; (bound form) butterfly |
| 加拿大 | Jiā ná dà | Canada |
| 墨 | Mò | surname Mo; abbr. for 墨西哥[Mo4 xi1 ge1], Mexico |
| 西 | Xī | the West; abbr. for Spain 西班牙[Xi1 ban1 ya2]; Spanish |
| 哥 | gē | elder brother |
| 穿越 | chuān yuè | to traverse; to pass through; to cross |
| 整 | zhěng | (bound form) whole; complete; entire; (before a measure word) whole; (before or after number + measure word) exactly; (bound form) in good order; tidy; neat; (bound form) to put in… |
| 个 | gě | used in 自個兒|自个儿[zi4 ge3 r5]; variant of 個|个[ge4] |
| 北美 | Běi měi | North America |
| 大 | dà | big; large; great; older (than another person); eldest (as in 大姐[da4 jie3]); greatly; freely; fully; (dialect) father; (dialect) uncle (father's brother) |
| 陆 | lǔ | land; continent; shore; to land; six (banker form); surname Lu |
| 这些 | zhè xiē | these |
| 动物 | dòng wù | animal |
| 没有 | méi yǒu | haven't; hasn't; doesn't exist; to not have; to not be |
| 地图 | dì tú | map; CL:張|张[zhang1],本[ben3] |
| 手 | shǒu | hand; (formal) to hold; person engaged in certain types of work; person skilled in certain types of work; personal(ly); convenient; classifier for skill; CL:雙|双[shuang1],隻|只[zhi1] |
| 机 | Jī | surname Ji |
| 任 | Rén | surname Ren |
| 何 | Hé | surname He |
| 现代 | Xiàn dài | Hyundai, South Korean company |
| 工具 | gōng jù | tool; instrument; utensil; means (to achieve a goal etc) |
| 那么 | nà me | like that; in that way; to that extent; (before a number) ... or so; about ...; then; in that case |
| 它 | tā | it; it (pronoun for an animal) |
| 们 | men | plural marker for pronouns, and nouns referring to individuals |
| 是 | shì | to be (followed by substantives only); correct; right; true; (respectful acknowledgement of a command) very well; (adverb for emphatic assertion); variant of 是[shi4] |
| 怎 | zěn | how |
| 么 | má | exclamatory final particle; variant of 麼|么[me5] |
| 找到 | zhǎo dào | to find |
| 方向 | fāng xiàng | direction; orientation |
| 的 | de | of; ~'s (possessive particle); (used after an attribute when it modifies a noun); (used at the end of a declarative sentence for emphasis); (used after a noun, verb or adjective to… |
| 科学家 | kē xué jiā | scientist |
| 经过 | jīng guò | to pass; to go through; process; course; CL:個|个[ge4] |
| 多年 | duō nián | many years; for many years; longstanding |
| 研究 | yán jīu | research; a study; CL:項|项[xiang4]; to research; to look into |
| 发现 | fā xiàn | to notice; to become aware of; to discover; to find; to detect; a discovery |
| 类 | lěi | kind; type; class; category; (bound form) to resemble; to be similar to |
| 拥有 | yōng yǒu | to have; to possess; to own |
| 多种 | duō zhǒng | many kinds of; multiple; diverse; multi- |
| 令人 | lìng rén | to cause one (to do sth); to make one (angry, delighted etc) |
| 惊 | jīng | to startle; to be frightened; to be scared; alarm |
| 叹 | tǎn | to sigh |
| 系 | xì | to connect; to relate to; to tie up; to bind; to be (literary); system; department; faculty; to tie; to fasten; to button up |
| 统 | tóng | to gather; to unify |
| 首先 | shǒu xiān | first of all; in the first place |
| 许多 | xǔ duō | many; a lot of; much |
| 可以 | kě yǐ | can; may; possible; able to; not bad; pretty good |
| 本身 | běn shēn | itself; in itself; per se |
| 就是 | jìu shì | exactly; precisely; only; simply; just; (used correlatively with 也[ye3]) even; even if |
| 一个 | yī ge | a; an; one; the whole (afternoon, summer vacation etc) |
| 巨大 | jù dà | huge; immense; enormous; gigantic |
| 磁铁 | cí tiě | magnet |
| 都 | Dū | surname Du |
| 有 | yǒu | to have; there is; (bound form) having; with; -ful; -ed; -al (as in 有意[you3 yi4] intentional) |
| 磁力线 | cí lì xiàn | line of magnetic flux |
| 眼睛 | yǎn jing | eye; CL:隻|只[zhi1],雙|双[shuang1] |
| 和 | hé | old variant of 和[he2]; surname He; (literary) harmonious (variant of 和[he2]) |
| 喙 | ||
| 部 | bù | ministry; department; section; part; division; troops; board; classifier for works of literature, films, machines etc |
| 含有 | hán yǒu | to contain; including |
| 一种 | yī zhǒng | one kind of; one type of |
| 特殊 | tè shū | special; particular; unusual; extraordinary |
| 物 | wù | (bound form) thing; (literary) the outside world as distinct from oneself; people other than oneself |
| 质 | zhǐ | character; quality; to pawn; hostage; Taiwan pr. [zhi2] |
| 感 | gǎn | to feel; to move; to touch; to affect; feeling; emotion; (suffix) sense of ~ |
| 知 | zhī | to know; to be aware |
| 强 | qiāng | strong; powerful; vigorous; better; to force (qiang3); stubborn (jiang4); surname Qiang |
| 度 | dù | to pass; to spend (time); measure; limit; extent; degree of intensity; degree (angles, temperature etc); kilowatt-hour; classifier for events and occurrences |
| 这就 | zhè jìu | immediately; at once |
| 像 | xiàng | to resemble; to be like; to look as if; such as; appearance; image; portrait; image under a mapping (math.) |
| 天生 | tiān shēng | nature; disposition; innate; natural |
| 就 | jìu | (after a suppositional clause) in that case; then; (after a clause of action) as soon as; immediately after; (same as 就是[jiu4 shi4]) merely; nothing else but; simply; just; precise… |
| 内置 | nèi zhì | built-in; internal |
| 无论 | wú lùn | no matter what or how; regardless of whether... |
| 哪 | nǎ | how; which |
| 里 | lǐ | variant of 裡|里[li3]; lining; interior; inside; internal; also written 裏|里[li3]; surname Li |
| 能 | Néng | surname Neng |
| 自己 | zì jǐ | oneself; (attributive) one's own |
| 相对 | xiāng duì | relatively; opposite; to resist; to oppose; relative; vis-a-vis; counterpart |
| 于 | Yú | surname Yu; (of time or place) in; at; on; (indicating any indirect relation) to; toward; vis-à-vis; with regard to; for; (indicating a source) from; out of; (used in comparison) than; (used i… |
| 磁 | cí | magnetic; magnetism; porcelain |
| 位置 | wèi zhi | position; place; seat; CL:個|个[ge4] |
| 人员 | rén yuán | staff; crew; personnel; CL:個|个[ge4] |
| 曾经 | céng jīng | once; already; former; previously; ever; (past tense marker used before verb or clause) |
| 用人 | yòng rén | servant; to employ sb for a job; to manage people; to be in need of staff |
| 工 | gōng | work; worker; skill; profession; trade; craft; labor |
| 干 | gān | old variant of 乾|干[gan1]; surname Gan; variant of 乾|干[gan1]; tree trunk; main part of sth; to manage; to work; to do; capable; cadre; to kill (slang); to fuck (vulgar); (coll.) pissed off; annoyed |
| 扰 | ráo | to disturb |
| 结 | jiē | (of a plant) to produce (fruit or seeds); Taiwan pr. [jie2] |
| 果 | guǒ | fruit; result; resolute; indeed; if really |
| 飞行 | fēi xíng | (of planes etc) to fly; flying; flight; aviation |
| 出现 | chū xiàn | to appear; to arise; to emerge; to show up |
| 了 | le | (completed action marker); (modal particle indicating change of state, situation now); (modal particle intensifying preceding clause); (bound form) clear in one's mind; to understand clearly |
| 明显 | míng xiǎn | clear; distinct; obvious |
| 偏 | pian | to lean; oblique; to deviate from average; stubbornly |
| 差 | chā | difference; discrepancy; (math.) difference (amount remaining after a subtraction); (literary) a little; somewhat; slightly |
| 从而 | cóng ér | thus; thereby |
| 证 | zhěng | to admonish |
| 明了 | míng liǎo | variant of 明瞭|明了[ming2 liao3] |
| 存 | cún | to exist; to deposit; to store; to keep; to survive |
| 其次 | qí cì | next; secondly |
| 也 | Yě | surname Ye |
| 会 | huì | can; to have the skill; to know how to; to be likely to; to be sure to; to meet; to get together; meeting; gathering; (suffix) union; group; association; (bound form) a moment (Tai… |
| 利用 | lì yòng | to exploit; to make use of; to use; to take advantage of; to utilize |
| 太阳 | tài yang | sun; sunlight; sunshine; temple (on the side of the human head) (abbr. for 太陽穴|太阳穴[tai4 yang2 xue2]) |
| 星星 | xīng xing | (coll.) a star; the stars in the sky |
| 来 | lái | to come; (used as a substitute for a more specific verb); hither (directional complement for motion toward the speaker, as in 回來|回来[hui2 lai5]); ever since (as in 自古以來|自古以来[zi4 gu3… |
| 白天 | bái tiān | daytime; during the day; day; CL:個|个[ge4] |
| 根 | gēn | root; basis; classifier for long slender objects, e.g. cigarettes, guitar strings; CL:條|条[tiao2]; radical (chemistry) |
| 据 | jǔ | according to; based on; evidence |
| 判 | pǎn | (bound form) to differentiate; to distinguish; to judge; to decide; to grade |
| 断 | duàn | to break; to snap; to cut off; to give up or abstain from sth; to judge; (usu. used in the negative) absolutely; definitely; decidedly |
| 同时 | tóng shí | at the same time; simultaneously |
| 体内 | tǐ nèi | within the body; in vivo |
| 计 | Jì | surname Ji |
| 算 | suàn | to calculate; to figure out; to include; to count in; to count; to be valid; to carry weight; to regard as; to consider (to be ...) |
| 时间 | shí jiān | (concept of) time; (duration of) time; (point in) time |
| 确定 | què dìng | definite; certain; fixed; to fix (on sth); to determine; to be sure; to ensure; to make certain; to ascertain; to clinch; to recognize; to confirm; OK (on computer dialog box) |
| 一 | yī | one; single; a (article); as soon as; entire; whole; all; throughout; "one" radical in Chinese characters (Kangxi radical 1); also pr. [yao1] for greater clarity when spelling out … |
| 天 | tiān | day; sky; heaven |
| 中 | Zhōng | (bound form) China; Chinese; surname Zhong |
| 不同 | bù tóng | different; distinct; not the same; not alike |
| 应 | Yīng | surname Ying; Taiwan pr. [Ying4] |
| 该 | gāi | should; ought to; probably; must be; to deserve; to owe; to be sb's turn to do sth; that; the above-mentioned |
| 天空 | tiān kōng | sky |
| 中的 | zhòng dì | to hit the target; (fig.) to hit the nail on the head |
| 个位 | gè wèi | the units place (or column) in the decimal system |
| 置 | zhì | to install; to place; to put; to buy |
| 晚上 | wǎn shang | evening; night; CL:個|个[ge4]; in the evening |
| 依 | yi | to depend on; according to |
| 靠 | kào | to lean against or on; to stand by the side of; to come near to; to depend on; to trust; to fuck (vulgar); traditional military costume drama where the performers wear armor (old) |
| 尤其是 | yóu qí shì | especially; most of all; above all; in particular |
| 星 | xīng | star; heavenly body; satellite; small amount |
| 附近 | fù jìn | nearby; neighboring; (in the) vicinity (of); neighborhood |
| 做 | zuò | to make; to produce; to write; to compose; to do; to engage in; to hold (a party etc); (of a person) to be (an intermediary, a good student etc); to become (husband and wife, frien… |
| 实验 | shí yàn | experiment; test; CL:個|个[ge4],次[ci4]; experimental; to experiment |
| 把 | bǎ | to hold; to grasp; to hold a baby in position to help it urinate or defecate; handlebar; classifier: handful, bundle, bunch; classifier for things with handles; (used to put the ob… |
| 放 | fàng | to put; to place; to release; to free; to let go; to let out; to set off (fireworks) |
| 人工 | rén gōng | artificial; manpower; manual work |
| 星空 | xīng kōng | starry sky; the star-studded heavens |
| 下 | xià | down; downwards; below; lower; later; next (week etc); second (of two parts); to decline; to go down; to arrive at (a decision, conclusion etc); measure word to show the frequency … |
| 改变 | gǎi biàn | to change; to alter; to transform |
| 跟着 | gēn zhe | to follow after; immediately afterwards |
| 除 | chú | to get rid of; to remove; to exclude; to eliminate; to wipe out; to divide; except; not including |
| 此 | cǐ | this; these |
| 之外 | zhī wài | outside; excluding |
| 还 | Huán | surname Huan |
| 地形 | dì xíng | topography; terrain; landform |
| 气 | qì | gas; air; smell; weather; to make angry; to annoy; to get angry; vital energy; qi |
| 味 | wěi | taste; (fig.) (noun suffix) feel; sense |
| 声音 | shēng yīn | sound; voice |
| 甚至 | shèn zhì | even; so much so that |
| 帮助 | bāng zhù | assistance; aid; to help; to assist |
| 够 | gòu | enough (sufficient); enough (too much); (coll.) (before adj.) really; (coll.) to reach by stretching out |
| 记 | jì | to record; to note; to memorize; to remember; mark; sign; classifier for blows, kicks, shots |
| 住 | zhù | to live; to reside; to stay; to stop; to cease; (result complement indicating firmness or a stable achieved state) |
| 山 | Shān | surname Shan |
| 河 | hé | river (CL:條|条[tiao2],道[dao4]); (bound form) the Yellow River; (bound form) the Milky Way; (bound form) (on restaurant menus) rice noodles 河粉[he2 fen3] |
| 流 | líu | to flow; to disseminate; to circulate or spread; to move or drift; to degenerate; to banish or send into exile; stream of water or sth resembling one; class, rate or grade |
| 海岸线 | hǎi àn xiàn | coastline; seaboard; shoreline |
| 形状 | xíng zhuàng | form; shape |
| 人 | rén | person; people; CL:個|个[ge4],位[wei4],名[ming2] |
| 熟悉 | shú xī | to be familiar with; to know well |
| 街道 | jiē dào | street; CL:條|条[tiao2]; subdistrict; residential district |
| 样 | yàng | manner; pattern; way; appearance; shape; classifier: kind, type |
| 有些 | yǒu xiē | some; somewhat; rather; a bit |
| 通过 | tōng guò | to pass through; to get through; to adopt (a resolution); to pass (legislation); to pass (a test); by means of; through; via |
| 闻 | Wén | surname Wen |
| 鸽 | ge | pigeon; dove |
| 子 | zǐ | son; child; seed; egg; small thing; 1st earthly branch: 11 p.m.–1 a.m., midnight, 11th solar month (7th December to 5th January), year of the rat; viscount, fourth of five orders o… |
| 被 | bèi | quilt; to cover (with); (literary) to suffer (a misfortune); used to indicate passive voice (placed before the doer of the action like "by" in English passive-voice sentences, or, … |
| 空气 | kōng qì | air; atmosphere |
| 地区 | dì qū | region; area (informal or geographical term); prefecture (in China's administrative system) |
| 最 | zuì | variant of 最[zui4]; old variant of 最[zui4]; (before an adjective or verb) to the highest degree; (the) most ...; -est; (after 之[zhi1]) best or most extreme example (e.g. 世界之最[shi4 jie4 zhi1 zui4] "the greatest in the world") |
| 讶 | yǎ | astounded |
| 力 | Lì | surname Li |
| 后 | Hòu | surname Hou; back; behind; rear; afterwards; after; later; post- |
| 学习 | xué xí | to learn; to study |
| 年轻 | nián qīng | young |
| 第 | dì | (prefix indicating ordinal number, as in 第六[di4 liu4] "sixth"); (literary) grades in which successful candidates in the imperial examinations were placed; (old) residence of a high… |
| 一次 | yī cì | first; first time; once; (math.) linear (of degree one) |
| 时 | shí | old variant of 時|时[shi2]; surname Shi |
| 跟随 | gēn suí | to follow |
| 年长 | nián zhǎng | senior |
| 过程 | guò chéng | course of events; process |
| 中学 | zhōng xué | middle school |
| 习 | Xí | surname Xi |
| 路线 | lù xiàn | itinerary; route; political line (e.g. right revisionist road); CL:條|条[tiao2] |
| 但 | dàn | but; yet; however; still; merely; only; just |
| 即 | jí | namely; that is; i.e.; prompt; at once; at present; even if; prompted (by the occasion); to approach; to come into contact; to assume (office); to draw near |
| 使 | shǐ | to make; to cause; to enable; to use; to employ; to send; to instruct sb to do sth; envoy; messenger |
| 单独 | dān dú | alone; by oneself; on one's own |
| 幼 | yòu | young |
| 大致 | dà zhì | more or less; roughly; approximately |
| 正确 | zhèng què | correct; sound; right; proper |
| 说明 | shuō míng | to explain; to illustrate; to indicate; to show; to prove; explanation; directions; caption; CL:個|个[ge4] |
| 部分 | bù fen | part; portion; piece; Taiwan pr. [bu4fen4] |
| 写 | xiě | to write |
| 提醒 | tí xǐng | to remind; to call attention to; to warn of |
| 我 | wǒ | I; me; my |
| 大自然 | dà zì rán | nature (the natural world) |
| 智慧 | zhì huì | wisdom; intelligence |
| 远 | yuǎn | far; distant; remote; (intensifier in a comparison) by far; much (lower etc) |
| 比 | Bǐ | Belgium; Belgian; abbr. for 比利時|比利时[Bi3 li4 shi2] |
| 想象 | xiǎng xiàng | to imagine; to envision; imagination |
| 复 | fù | to go and return; to return; to resume; to return to a normal or original state; to repeat; again; to recover; to restore; to turn over; to reply; to answer; to reply to a letter; …; to repeat; to double; to overlap; complex (not simple); compound; composite; double; diplo-; duplicate; overlapping; to duplicate; variant of 復|复[fu4]; to reply to a letter |
| 杂 | zá | variant of 雜|杂[za2]; mixed; miscellaneous; various; to mix |
| 花 | Huā | surname Hua; old variant of 花[hua1]; variant of 花[hua1]; flower; blossom; also pr. [wei3] |
| 几千 | jǐ qiān | several thousand |
| 年 | Nián | surname Nian; grain; harvest (old); variant of 年[nian2] |
| 才 | cái | ability; talent; sb of a certain type; a capable individual; then and only then; just now; (before an expression of quantity) only; (emphatic, esp. in contrast or correction) reall…; (variant of 才[cai2]) just now; (variant of 才[cai2]) (before an expression of quantity) only |
| 发明 | fā míng | to invent; an invention; CL:個|个[ge4] |
| 出 | chū | to go out; to come out; to arise; to occur; to produce; to yield; to go beyond; to exceed; (used after a verb to indicate an outward direction or a positive result); classifier for…; variant of 出[chu1] (classifier for plays or chapters of classical novels) |
| 而 | ér | and; as well as; and so; but (not); yet (not); (indicates causal relation); (indicates change of state); (indicates contrast) |
| 数百万 | shù bǎi wàn | several million |
| 年前 | nián qián | by the end of the year; at the end of the year; shortly before New Year |
| 已经 | yǐ jīng | already |
| 这 | zhè | (pronoun) this; these; (bound form) this; the (followed by a noun); (bound form) this; these (followed by a classifier) (in this sense, commonly pr. [zhei4], esp. in Beijing) |
| 更 | gēng | to change or replace; to experience; one of the five two-hour periods into which the night was formerly divided; watch (e.g. of a sentry or guard) |
| 精妙 | jīng miào | exquisite; fine and delicate (usu. of works of art) |
| 也许 | yě xǔ | perhaps; maybe |
| 对 | duì | right; correct; towards; at; for; concerning; regarding; to treat (sb a certain way); to face; (bound form) opposite; facing; matching; to match together; to adjust; to fit; to sui… |
| 自然界 | zì rán jiè | nature; the natural world |
| 了解 | liǎo jiě | to understand; to know about; to learn about; to find out |
| 远远 | yuǎn yuǎn | distant; by far |
| 不够 | bù gòu | not enough; insufficient; inadequate |
Every year, billions of birds undertake long-distance migrations across the Earth. Arctic terns fly from the Arctic to the Antarctic, a one-way journey of over 70,000 kilometers. Monarch butterflies fly from Canada to Mexico, crossing the entire North American continent. These animals have no maps, no phones, and no modern navigation tools. So how do they find their way? After years of research, scientists have discovered that birds possess multiple amazing navigation systems.
First, many birds can sense the Earth’s magnetic field. The Earth itself is a giant magnet, with magnetic field lines running from the South Pole to the North Pole. Scientists have found that birds’ eyes and beaks contain a special substance that can detect the direction and intensity of magnetic fields. It’s as if birds are born with a built-in compass – no matter where they fly, they can sense their position relative to the magnetic poles. Researchers once used artificial magnetic fields to interfere with bird migration, and found that the birds’ flight direction showed significant deviation, thus proving the existence of magnetic field sensing.
Second, birds also use the sun and stars to navigate. During the day, they determine direction based on the sun’s position, while using their internal biological clock to calculate time, thereby determining where the sun should be in the sky at different times of day. At night, many birds rely on stars for navigation, especially the constellations near the North Star. Scientists conducted experiments placing birds under an artificial night sky and changing the positions of constellations, and found that the birds’ flight direction changed accordingly.
Beyond this, birds also use terrain, smells, sounds, and even infrasound to help navigate. They can remember the shapes of mountains, rivers, and coastlines, just like humans remember familiar streets. Some birds can even determine their location by smell – pigeons have been found to use the different regional scents in the air to determine direction.
Most surprisingly, some of these navigation abilities are innate, while others are learned. Young birds follow older birds during their first migration, learning the route during flight. But even young birds migrating alone for the first time can roughly find the correct direction, indicating that some navigation abilities are written in their genes.
Birds’ navigation systems remind us that nature’s wisdom is far more complex than we imagine. It took us thousands of years to invent the compass and GPS, yet birds possessed navigation systems more sophisticated than these millions of years ago. Perhaps our understanding of the natural world is still far from enough.