Compared to the rest of the shrikes, the Fiscal Shrike is quite unusual in that a pair will hold a territory throughout the year.  Most of the true shrike species (genus Lanius) from the northern hemisphere are migratory, breeding in the northern hemisphere and spending the austral summer in the southern hemisphere.

The Fiscal Shrike is raptorial and feeds on a wide range of invertebrates, notably insects and small vertebrates.  Vertebrates comprise a very small portion of its diet and most of its prey are those considered pests to the farmer or gardener.  Its main hunting method is sit-and-wait foraging and about three-quarters of its day is spent on the lookout for prey.  It also hovers before pouncing and chases and flushes prey out of undergrowth.  When flying insects are numerous, such as when winged termites emerge from the ground, the bird will hunt on the wing and in very windy conditions when flight becomes impossible, it will glean prey from foliage.

Like many other shrikes, Fiscals impale some of their prey on thorns, sticks and barbed wire, sometimes whiles still alive, which has lead to their reputation as being “ruthless killers”.  This behaviour, known as caching, is not unnecessary killing for the sake of killing.   Caching may have many functions, the most obvious of which is as a larder that is provisioned when there is an excess of prey and utilised when prey is scarce.  Impaling large prey may also help the bird manipulate the prey when the time comes to eat it.  A more interesting hypothesis is that males use caches to advertise their fitness to potential partners – a male that is able to catch more prey than is needed for his own maintenance, either through his superior hunting ability or the quality of his territory, should be able to provision a partner and offspring.

In KwaZulu Natal Fiscal Shrikes breed mainly between the months of August and January, with most eggs being laid in September and October.

Courtship begins when the male starts to feed his partner to increase her condition in preparation for egg laying or simply to strengthen their bond.  The female relentlessly follows her mate around their territory begging for food in a manner similar to most young birds.

Both sexes search out a suitable nesting site, usually a thorny tree or shrub between two and five metres high, but Fiscal Shrikes have been recorded as using buildings, reeds, bamboo and epiphytes on which to place their nest.

Once a suitable site has been found, the male Fiscal Shrike performs a nest display by entering the tree with nesting material and slowly moving through the canopy until the site is reached.  At the site he deposits the material, sits on it and begins softly calling to his partner whilst quivering his wings and fanning his tail.  The display complete, the male moves to the top of the tree and perches prominently for few minutes before repeating the performance again and again.  These displays probably serve to entice the female to nesting, as the male does little of the actual nest building, only supplying material to the female.

Fiscal Shrike lay three or four pale, speckled eggs and the female alone incubates the clutch, spending about 80% of her time at the nest.  Her partner continues to feed her during this period, although she also leaves the nest to forage.  In KwaZulu Natal, female Fiscal Shrike shade their eggs in hot weather and the length of time they devote to shading increases as the temperature rises.  It is also possible that females stand over their eggs in order to regulate their own body temperature by raising their bodies into their air current.

Eggs hatch about two and a half weeks after being laid, usually over a period of two days and often one or two eggs fail to hatch.  Both the female and mail provision their offspring and the female continues to incubate and shade the clutch until fledging occurs.