**2.5 The case of the northern raven on the Island of Fuerteventura (Las Palmas province, Canary Islands, Spain)**

The population of northern raven (*Corvus corax canariensis),* an endemic subspecies of the Canary Islands, "reaches 1,300 specimens, according to the General Directorate of the Environment of the Canary Government, which rejects that they cause significant damage to livestock" (**Figure 16**).

"According to the study carried out in these four years by the General Directorate for the Fight against Climate Change and the Environment of the Government of the Canary Islands on the population of crows in Fuerteventura and the control of the damages produced in the field and livestock, the number of

**107**

many cases …

incidence [33].

**Figure 16.**

population [32].

their continuity [32].

*The Limit to the Density of Species (A Reflection on Human Intervention in Conservation...*

specimens would be around 1,300 with a density fluctuation between 0.81 and 0.96 individuals per square kilometer. In terms of damage, only six incidents per year have been reported in a total of 163 livestock farms, which indicates a 'very limited'

*The northern raven (canary race) has reached overpopulation on the island of Fuerteventura. Photo F. del Río.*

The incidence of ravens, "not so limited", occurs on endemic populations of reptiles, which are experiencing such loss of numbers that their survival is in danger. It is urgently necessary to establish limits to the density of the raven

Ornithologists residing on the island indicate that the increase in the density of this species has its origin in the contributions of farm animal remains, which are carried out weekly at two specific points on the island. The productivity of the breeding pairs of crows is currently maximum (4–5 chicks per nest). The high number of specimens, causes them to no longer find places to install their nests, even building them at an exceptionally low height, on fig trees. They warn of the impact they are causing on endemic reptile populations, seriously compromising

The contribution of food by man has produced the desired effect, in its day, which was to increase the population of this subspecies of raven. However, a limit to its density has not been established. Once the recovery program has started, it has not been marked where to stop. If now the weekly contributions to the dumps were stopped abruptly, the ravens would have a much greater impact on their captures of reptiles, reaching a certain extinction. It seems urgent and essential, a biological control of the raven, to establish a number, in order to allow to maintain the subspe-

There is no shortage of examples of very worrying situations, which reach this qualification due to the inaction of governments and "animalistic" civil society, which treats and grants animals the same rights as humans, and even more¨:

The case of "escapes" from private collections and zoos; the case of the release

of pets, by individuals; the case of domestic and feral cats; the case of … so

cies and, at the same time and level, the endemic reptiles of the island. In none of the above cases can the "the more the better" be validated.

*DOI: http://dx.doi.org/10.5772/intechopen.97436*

*The Limit to the Density of Species (A Reflection on Human Intervention in Conservation... DOI: http://dx.doi.org/10.5772/intechopen.97436*

#### **Figure 16.** *The northern raven (canary race) has reached overpopulation on the island of Fuerteventura. Photo F. del Río.*

specimens would be around 1,300 with a density fluctuation between 0.81 and 0.96 individuals per square kilometer. In terms of damage, only six incidents per year have been reported in a total of 163 livestock farms, which indicates a 'very limited' incidence [33].

The incidence of ravens, "not so limited", occurs on endemic populations of reptiles, which are experiencing such loss of numbers that their survival is in danger. It is urgently necessary to establish limits to the density of the raven population [32].

Ornithologists residing on the island indicate that the increase in the density of this species has its origin in the contributions of farm animal remains, which are carried out weekly at two specific points on the island. The productivity of the breeding pairs of crows is currently maximum (4–5 chicks per nest). The high number of specimens, causes them to no longer find places to install their nests, even building them at an exceptionally low height, on fig trees. They warn of the impact they are causing on endemic reptile populations, seriously compromising their continuity [32].

The contribution of food by man has produced the desired effect, in its day, which was to increase the population of this subspecies of raven. However, a limit to its density has not been established. Once the recovery program has started, it has not been marked where to stop. If now the weekly contributions to the dumps were stopped abruptly, the ravens would have a much greater impact on their captures of reptiles, reaching a certain extinction. It seems urgent and essential, a biological control of the raven, to establish a number, in order to allow to maintain the subspecies and, at the same time and level, the endemic reptiles of the island.

In none of the above cases can the "the more the better" be validated.

There is no shortage of examples of very worrying situations, which reach this qualification due to the inaction of governments and "animalistic" civil society, which treats and grants animals the same rights as humans, and even more¨:

The case of "escapes" from private collections and zoos; the case of the release of pets, by individuals; the case of domestic and feral cats; the case of … so many cases …

*Birds - Challenges and Opportunities for Business, Conservation and Research*

**2.4 The case of the cattle heron on the Island of Lanzarote (Las Palmas** 

the winter in the Canary Islands, due to the lack of food at that time in Africa,

An island is a very sensitive ecosystem. Not acting is irresponsible [32].

"According to the study carried out in these four years by the General Directorate for the Fight against Climate Change and the Environment of the Government of the Canary Islands on the population of crows in Fuerteventura and the control of the damages produced in the field and livestock, the number of

**2.5 The case of the northern raven on the Island of Fuerteventura (Las Palmas** 

The population of northern raven (*Corvus corax canariensis),* an endemic subspecies of the Canary Islands, "reaches 1,300 specimens, according to the General Directorate of the Environment of the Canary Government, which rejects that they

colony on the island, which reaches 1,500 individuals (**Figure 15**).

Cattle heron (*Bubulcus ibis*) makes migratory movements from Africa to spend

Accidentally a wounded specimen could be cared for by a human and attracted a couple, getting to reproduce on the island of Lanzarote and starting a breeding

This population, that nest in the city of Arrecife, the island's capital, is seriously endangering the conservation of endemic reptile species, which they capture as the basis of their diet. The authorities do not solve the problem firmly. They are allowing the disappearance of reptiles and causing damage to other species of birds on

**Province, Canary Islands, Spain)**

*Cattle heron on a sheep. Photo F. del Río.*

returning to the continent to reproduce.

**province, Canary Islands, Spain)**

cause significant damage to livestock" (**Figure 16**).

the island (**Figure 15**).

**Figure 15.**

**106**
