The Glorified Allah commands:
وَمَثَلُ الَّذِينَ كَفَرُواْ كَمَثَلِ الَّذِي يَنْعِقُ بِمَا لاَ يَسْمَعُ إِلاَّ دُعَاء وَنِدَاء صُمٌّ بُكْمٌ عُمْيٌ فَهُمْ لاَ يَعْقِلُونَ.
“And the parable of those who conceal (kafir) is as the parable of a crow which cries at a sound that it does not listen to. Which it hears is no more than a call and a cry; deaf, dumb (and) blind. They do not use their reason.” (Al-Baqara/The Cow 2:171)
The term(نعق ينعِق)=na’q in the verse stands both for crow’s sound and for cry of shepherd to the cattle to prevent them from walking 
. The commentary books have assigned the second meaning to the word putting the verse in an incomprehensible situation; later they forced themselves to explanations that are not proper according to the original text. Let’s give some examples from English commentary books:
Saheeh International Translation:
“The example of those who disbelieve is like that of one who shouts at what hears nothing but calls and cries cattle or sheep – deaf, dumb and blind, so they do not understand. “
The sentence: “الَّذِي يَنْعِقُ بِمَا لاَ يَسْمَعُ إِلاَّ دُعَاًءً وَنِدَاءً” cannot possibly be translated as “who shouts at what hears nothing but calls and cries cattle or sheep”.
The Translation of Muhammad Asad:
“And so, the parable of those who re bent on denying the truth is that of the beast which hears the shepherd’s cry, and hears in it nothing but the sound of a voice and a call. Deaf are they, and dumb, and blind: for they do not use their reason. “
The term (نعق ينعِق)=na’q in this sentence is translated as “hearing the shepherd’s cry”, although it might only mean “crying (of the shepherd)” without the addition of ‘hearing’. So this translation cannot be correct, either.
Many other translations have carried the previous mistakes to nowadays. The reason of these mistakes is that relations between verses are not noticed. With some attention, the metaphore in the following verse would have shown the other verse’s meaning. The Glorified Allah commands:
وَلَقَدْ ذَرَأْنَا لِجَهَنَّمَ كَثِيرًا مِنَ الْجِنِّ وَالْإِنْسِ لَهُمْ قُلُوبٌ لَا يَفْقَهُونَ بِهَا وَلَهُمْ أَعْيُنٌ لَا يُبْصِرُونَ بِهَا وَلَهُمْ آَذَانٌ لَا يَسْمَعُونَ بِهَا أُولَئِكَ كَالْأَنْعَامِ بَلْ هُمْ أَضَلُّ أُولَئِكَ هُمُ الْغَافِلُونَ.
“And it has come to pass that We created most of the jinn and the men for hell; they have hearts with which they do not comprehend, and they have eyes with which they do not see, and they have ears with which they do not hear; they are as ‘an’am’; nay, they are lower; these are the heedless ones. 
” (Al-A’raf/ Purgatory 7:179)
‘An’am’ means sheep, cows and camels
. There is not a single word corresponding to this in English. In many translations it has been interpreted as “cattle”. This interpretation is not right as camel is not included in cattle, but in an’am.
Sheep, cows and camels are animals of beneficial purpose. As the disbelievers are considered of less value, the animal in the simile must be lower than cattle. Therefore we understand that: in the 171st verse of Al-Baqara the word (ينعِق = yen’iqu) has been used to identify the crow’s sound, which is lower than cattle.
In fact, crow is lower than ‘an’am’ as it feeds on carrion, eggs, and with small and baby bids. It looks inside the garbage to be fed. It damages the plants of crop, the fruit trees, the vegetables and the vines. It has a developed capability and can be domesticated easily
In this verse that gives the definition of concealers (kafirun), you can notice plenty of similarity with crows:
وَإِذَا تَوَلَّى سَعَى فِي الْأَرْضِ لِيُفْسِدَ فِيهَا وَيُهْلِكَ الْحَرْثَ وَالنَّسْلَ.
“And when he turns back, he runs along in the land that he may cause mischief in it and destroy the resources and the generation, and Allah does not love mischief-making.” (Al-Baqara/The Cow 2:205)
Those who are not careful with the connection between verses had interpreted the previous verse- the 179th verse of A’raf as “They are even more deviant than them.” or “They are even more pervert than them.” As there is no motive to define the sheep, the cows and camels as such, this explanation ends to be mistaken as well.
The relation concealer-crow can be noticed in the issue of Cain and Abel. Cain straying from the right path and killing his brother finds himself in a worse position than a crow. The verses relating this event are:
وَاتْلُ عَلَيْهِمْ نَبَأَ ابْنَيْ آَدَمَ بِالْحَقِّ إِذْ قَرَّبَا قُرْبَانًا فَتُقُبِّلَ مِنْ أَحَدِهِمَا وَلَمْ يُتَقَبَّلْ مِنَ الْآَخَرِ قَالَ لَأَقْتُلَنَّكَ قَالَ إِنَّمَا يَتَقَبَّلُ اللَّهُ مِنَ الْمُتَّقِينَ. لَئِنْ بَسَطْتَ إِلَيَّ يَدَكَ لِتَقْتُلَنِي مَا أَنَا بِبَاسِطٍ يَدِيَ إِلَيْكَ لِأَقْتُلَكَ إِنِّي أَخَافُ اللَّهَ رَبَّ الْعَالَمِينَ. إِنِّي أُرِيدُ أَنْ تَبُوءَ بِإِثْمِي وَإِثْمِكَ فَتَكُونَ مِنْ أَصْحَابِ النَّارِ وَذٰلِكَ جَزَاءُ الظَّالِمِينَ. فَطَوَّعَتْ لَهُ نَفْسُهُ قَتْلَ أَخِيهِ فَقَتَلَهُ فَأَصْبَحَ مِنَ الْخَاسِرِينَ. فَبَعَثَ اللَّهُ غُرَابًا يَبْحَثُ فِي الْأَرْضِ لِيُرِيَهُ كَيْفَ يُوَارِي سَوْأَةَ أَخِيهِ قَالَ يَا وَيْلَتَا أَعَجَزْتُ أَنْ أَكُونَ مِثْلَ هَذَا الْغُرَابِ فَأُوَارِيَ سَوْأَةَ أَخِي فَأَصْبَحَ مِنَ النَّادِمِينَ
“And relate to them the story of the two sons of Adam with truth when they both offered an offering, but it was accepted from one of them and was not accepted from the other. He said: I I will most certainly slay you. (The other) said: Allah only accepts from those who guard (against evil).
[5:28] If you will stretch forth your hand towards me to slay me, I am not one to stretch forth my hand towards you to slay you surely I fear Allah, the Lord of the worlds:
[5:29] Surely I wish that you should bear the sin committed against me and your own sin, and so you would be of the inmates of the fire, and this is the recompense of the unjust.
[5:30] Then his mind facilitated to him the slaying of his brother so the other one slew him; then he became of the losers.
[5:31] Then Allah sent a crow digging up the earth so that He might show him how he should cover the dead body of his brother. He said: Woe to me! Aren’t I as capable as that crow that I did not cover the dead body of my brother? So he became of those who regret.” (Al-Ma’eda/The Feast 5:27-31)
Ibn Manzur, Lisan al-arab, art.نعق .
The word translated as ‘lower’ (الأضل)
stems from the root ‘dalalat’ in Arabic; and means, straying and being in a low position. (Lisan al-arab art. ضلل
Mufradat, Raghib Esfahani; art. نعم
The Big Larousse Encyclopedia and Dictionary, Istanbul, 1986, Book XI, page 6423.